kth.sePublications
Change search
Refine search result
12 1 - 50 of 63
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Benedikt Maria Köhnlein, M.
    et al.
    Abitbol, T.
    Osório Oliveira, A.
    Magnusson, M. S.
    Adolfsson, Karin H.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Svensson, S. E.
    Ferreira, J. A.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Zamani, A.
    Bioconversion of food waste to biocompatible wet-laid fungal films2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 216, p. 110534-, article id 110534Article in journal (Refereed)
    Abstract [en]

    The fungus Rhizopus delemar was grown on bread waste in a submerged cultivation process and wet-laid into films. Alkali or enzyme treatments were used to isolate the fungal cell wall. A heat treatment was also applied to deactivate biological activity of the fungus. Homogenization of fungal biomass was done by an iterative ultrafine grinding process. Finally, the biomass was cast into films by a wet-laid process. Ultrafine grinding resulted in densification of the films. Fungal films showed tensile strengths of up to 18.1 MPa, a Young's modulus of 2.3 GPa and a strain at break of 1.4%. Highest tensile strength was achieved using alkali treatment, with SEM analysis showing a dense and highly organized structure. In contrast, less organized structures were obtained using enzymatic or heat treatments. A cell viability assay and fluorescent staining confirmed the biocompatibility of the films. A promising route for food waste valorization to sustainable fungal wet-laid films was established.

  • 2. Bressi, Sara
    et al.
    Dumont, A. G.
    Partl, Manfred
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials. Carleton Univ, Ottawa, Canada.
    An advanced methodology for the mix design optimization of hot mix asphalt2016In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 98, p. 174-185Article in journal (Refereed)
    Abstract [en]

    The bitumen quantity to add to asphalt mixtures depends on the surfaces of aggregates and filler to be coated. The formulas currently available in the literature have limitations such as considering all the fillers with the same specific surface or the aggregates with spherical or cubical shapes. This paper aims to define an analytical approach for the determination of the optimal dosage of bitumen in HMA proposing new methodologies to go a step further in the resolution of the above mentioned approximations. Indeed, new surface area factors were calculated to determine the aggregates surface considering their real shapes and volumes. Afterwards, the authors proposed a detailed characterization of two types of fillers and the critical filler concentration, introduced by Faheem and Bahia, was used to calculate the minimum amount of bitumen for maintaining the mastic in a diluted state and filling the voids in the mixtures. Finally, a verification of the formula developed was carried out with specific laboratory tests. These results allow the challenge of revising the method of calculating the specific surface of the aggregates and filler to be addressed with the final goal to include them in a new mix design optimization for HMA. 

  • 3.
    Carosio, Federico
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Cuttica, Fabio
    Medina, Lilian
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Biocomposites. KTH, School of Chemical Science and Engineering (CHE), Centres, Wallenberg Wood Science Center.
    Clay nanopaper as multifunctional brick and mortar fire protection coating: Wood case study2016In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 93, p. 357-363Article in journal (Refereed)
    Abstract [en]

    Abstract Wood is one of the most sustainable, esthetically pleasing and environmentally benign engineering materials, and is often used in structures found in buildings. Unfortunately, the fire hazards related to wood are limiting its application. The use of transparent cellulose nanofiber (CNF)/clay nanocomposites, with unique brick-and-mortar structure, is proposed as a sustainable and efficient fire protection coating for wood. Fire performance was assessed by cone calorimetry. When exposed to the typical 35 kW/m2 heat flux of developing fires, the time to ignition of coated wood samples increased up to about 4 1/2 min, while the maximum average rate of heat emission (MARHE) was decreased by 46% thus significantly reducing the potential fire threat from wood structures.

  • 4.
    Celma Cervera, Carlos
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Jelagin, Denis
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Partl, Manfred N.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials. bEMPA Swiss Federal Laboratories for Materials Testing and Research, Switzerland.
    Larsson, Per-Lennart
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Contact-induced deformation and damage of rocks used in pavement materials2017In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 133, p. 255-265Article in journal (Refereed)
    Abstract [en]

    Performance of stone-based construction materials, such as asphalt and unbound aggregate mixtures is defined to a great extent by the mechanics of the stone-to-stone interactions. Accordingly, the Discrete Element Method (DEM) is gaining popularity as a modelling tool to investigate the mechanical behavior of these materials. Contact and failure laws defining particles force-displacement relationships and the propensity of particles to break are crucial inputs for the DEM simulations. The present study aims at providing an experimental contact mechanics basis for the development of physically based stone-to-stone interaction laws. The attention is focused on investigating stone's force-displacement relationship and damage characteristics at pure normal loading for two stone materials used by the road industry. Experiments are performed at spherical contact profiles for cyclic and monotonically increasing loads. The emphasis lies on the evolution of contact compliance and accumulation of contact induced damage. The effect of surface roughness on the materials response is examined through comparative experiments performed on the specimens with different roughness values. Optical and environmental scanning electron microscopy (ESEM) observations of the contact induced damage at the material surface are presented and discussed in the context of contact mechanics. The implications of the reported experimental findings on the development of mechanics based contact and failure laws for the DEM modelling of stone-based construction materials are discussed.

  • 5.
    Chen, Feng
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Balieu, Romain
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    A state-of-the-art review of intrinsic and enhanced electrical properties of asphalt materials: theories, analyses and applications2020In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 195, p. 109067-Article in journal (Refereed)
    Abstract [en]

    In pavement engineering, a variety of promising application technologies are found relying on a thorough understanding of the intrinsic (mainly dielectric) electrical properties of asphalt binder and concrete materials. Meanwhile, the electrical properties of asphalt materials can be further enhanced by introducing conductive additives into and it has been brought to light that, the electrically conductive asphalt is becoming an emerging subject of interest that caters to the concept of a multifunctional pavement future. In context of these, this paper presents a holistic overview of the intrinsic and enhanced electrical properties of asphalt materials, including the theoretical analyses, as well as the corresponding applications in the practice. From such a state-of-the-art review, it is worth noting that: i) an improved understanding of asphalt material has been achieved by an in-depth examination of its electrical properties; ii) the increased significance of the research domain as a whole and, the key importance of multidisciplinary collaborations for future successes, have been indicated.

  • 6.
    Choi, Young Won
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Dong, Zhihua
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Li, Wei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Schönecker, Stephan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Kim, Hansoo
    Korea Univ, Inst High Technol Mat & Devices, Seoul 02841, South Korea..
    Kwon, Se Kyun
    Pohang Univ Sci & Technol, Dept Phys, Pohang 37673, South Korea..
    Vitos, Levente
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Predicting the stacking fault energy of austenitic Fe-Mn-Al (Si) alloys2020In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 187, article id 108392Article in journal (Refereed)
    Abstract [en]

    Aluminum and silicon are common alloying elements for tuning the stacking fault energy (SFE) of high Mn steels. Today the theoretical investigations on the Fe-Mn-Al/Si systems using Density Functional Theory (DFT) are very scarce. In the present study, we employ a state-of-the-art longitudinal spin fluctuations (LSFs) model in combination with DFT for describing the magnetic effects in Fe-Mn based alloys at finite temperature. We find that the traditional DFT-floating spin results fail to explain the experimental trends. However, the DFT-LSFs approach properly captures the Al-induced increase and Si-induced decrease of the SFE of the base alloy in line with the room-temperature observations. This finding highlights the importance of LSFs in describing the Al/Si effects on the SEE of Fe-Mn based alloys. We point out that the effects of the non-magnetic Al and Si additions on the SEE are in fact determined by the magnetic state of the host matrix. In addition, we estimate the role of carbon addition in the alloying effects of Al and Si. The present results provide a convenient pathway to access the important mechanical parameters for designing advanced high-strength alloys.

  • 7.
    Croné, Philip
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Zhou, Tao
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    Hedström, Peter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    Odqvist, Joakim
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    Gudmundson, Peter
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Faleskog, Jonas
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Continuum plasticity modelling of work hardening for precipitation-hardened martensitic steel guided by atom probe tomography2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 215, article id 110463Article in journal (Refereed)
    Abstract [en]

    An analytical flow stress model, based on isotropic strain gradient plasticity theory, for precipitation hardened materials, is proposed and evaluated against tensile data on a 15 wt% Cr - 5 wt% Ni (15-5) PH stainless steel. The 15-5 PH material was aged at 500 °C for 1 h, 2 h, 5 h and 50 h to obtain a wide range of precipitate sizes. Detailed characterisation of precipitates was obtained using atom probe tomography (APT). A second material, a 15-5 stainless steel without added Cu was heat treated to obtain a similar matrix microstructure as in the 15-5 PH, but without Cu precipitates. Tensile testing revealed that the heat treated 15-5 PH material covered the full range from under- to overaged conditions. The analytical model, which accounts for stress reducing effects of plastic relaxation around particles, manages to capture the experimental data in a very satisfying manner using only a total of three tunable parameters. It is believed that the proposed model can offer an alternative to the much more commonly used work hardening models based on the internal variable approach.

    Download full text (pdf)
    fulltext
  • 8.
    Dai, J. H.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. Harbin Inst Technol Weihai, Sch Mat Sci & Engn, 2 West Wenhua Rd, Weihai 264209, Peoples R China..
    Li, Wei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Song, Y.
    Harbin Inst Technol Weihai, Sch Mat Sci & Engn, 2 West Wenhua Rd, Weihai 264209, Peoples R China..
    Vitos, Levente
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. Uppsala Univ, Dept Phys & Astron, Div Mat Theory, Box 516, SE-75120 Uppsala, Sweden.;Wigner Res Ctr Phys, Inst Solid State Phys & Opt, POB 49, H-1525 Budapest, Hungary..
    Theoretical investigation of the phase stability and elastic properties of TiZrHfNb-based high entropy alloys2019In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 182, article id UNSP 108033Article in journal (Refereed)
    Abstract [en]

    First principles calculations are performed to study the effects of alloying elements (X = Al, Si, Sc, V, Cr, Mn, Cu, Zn, Y. Mo, Ta, W and Re) on the phase stability and elastic properties of TiZrHfNb refractory high entropy alloys. Both equimolar and non-equimolar alloys are considered. It is shown that the calculated lattice parameters, phase stability and elastic moduli of equimolar TiZrHfNbX are consistent with the available experimental and theoretical results. The substitutions of alloying elements at Ti, Zr, and Hf sites with various contents show similar effects on the phase stability and elastic properties of the TiZrHINb-based alloys. The substitutions on Nb site are found to generally decrease the stability of body centered cubic phase. Close connections between the charge densities at the Wigner-Seitz cell boundary and the bulk moduli of TiZrHfNb-based alloys are found. The present results provide a quantitative model for exploring the phase stability and elastic properties of TiZrHINb-based alloys from the electronic structure viewpoint. Elsevier Ltd.

  • 9. Davydova, A.
    et al.
    Eriksson, J.
    Chen, R.
    Rudisch, K.
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. University of Oslo, Norway.
    Scragg, J. J. S.
    Thio-olivine Mn2SiS4 thin films by reactive magnetron sputtering: Structural and optical properties with insights from first principles calculations2018In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 152, p. 110-118Article in journal (Refereed)
    Abstract [en]

    Thio-olivines such as (Fe,Mn)2(Si,Ge)S4 have been proposed as candidate earth-abundant materials for single and multi-junction solar cells. In this work we present the first investigation of Mn2SiS4thin films prepared by reactive magnetron sputtering deposition, using a composition grading approach. Precursor instability in ambient conditions is observed, revealing the oxidation/hydrolysis of Si–S bonds from the as-deposited film as a blocking mechanism for the ternary compound formation. Structural, morphological and optical properties of the annealed Mn2SiS4 films are reported for the first time. Resulting Mn2SiS4 films have orthorhombic Pnma structure and are polycrystalline. Raman active modes at 325 nm excitation are observed at 262, 320, 400 and 464 cm−1. From room temperature photoluminescence at 532 nm excitation the band gap is estimated to be about 1.9 eV, but a high optical absorption coefficient of >104 cm−1 was only obtained at E > 2.8 eV. First principles calculations are used for better understanding of opto-electronic properties. From the calculations, Mn2SiS4 is suggested to have a band gap of about 1.73–1.86 eV depending on the magnetic configuration of Mn and slight indirect nature. The slow absorption onset is interpreted by strong anisotropy due to one of the components of the dielectric function.

  • 10.
    Espinoza-Cuadra, J.
    et al.
    CONACyT-México, Av. Insurgentes Sur 1582, Col. Crédito Constructor Del. Benito Juárez, C.P. 03940, Mexico, D.F., Mexico.
    Gallegos-Acevedo, P.
    Universidad Tecnológica de la Mixteca, Carretera a Acatlima Km. 2.5 Huajuapán de León, C.P. 69000, Oaxaca, Mexico.
    Mancha-Molinar, H.
    Research and Development Department, CIFUNSA, Blvd. Isidro López Z. #4003, Zona Industrial Saltillo, C.P. 25230, Coahuila, Mexico.
    Picado, Apolinar
    Natl Univ Engn UNI, Fac Chem Engn.
    Effect of Sr and solidification conditions on characteristics of intermetallic in Al–Si 319 industrial alloys2010In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 31, no 1, p. 343-356Article in journal (Refereed)
    Abstract [en]

    An experimental study was carried out to determine the effect of strontium (Sr) on the characteristic of intermetallic phases, particularly the Al5FeSi phase which present morphology of platelets or needle-like. The results showed that within the range of variables studied, the modification process caused the disappearance of the needles and only occur the precipitation of phase α (chinese script-like). Refinement of the intermetallic phases occurs in conjunction with the refinement in grain size. Both parameters depend strongly on local cooling rate (T), temperature gradient (G) and apparent rate of solidification front (V). In the case of equiaxed structures the refinement of grain size and intermetallic occurs with increasing local cooling rate and temperature gradient and decrease the apparent rate of solidification front. In the case of columnar structures, refinement of grains and intermetallic requires the increase in values of the three variables indicated. Moreover, the addition of Sr resulted in the modification of silicon eutectic, as noted in others research works.

  • 11.
    Gao, Ying
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China.
    Ram, Farsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Chen, Bin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Garemark, Jonas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Dai, Hongqi
    Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China.
    Li, Yuanyuan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Scalable hierarchical wood/ZnO nanohybrids for efficient mechanical energy conversion2023In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 226, article id 111665Article in journal (Refereed)
    Abstract [en]

    Owing to the hierarchical structure, easy multi-functionalization and favorable mechanical properties, wood could harvest electricity from mechanical energy through piezoelectric behavior. In this work, a scalable method to synthesize wood/ZnO composite with multilayered ZnO morphologies is reported for efficient mechanical energy conversion. The synthesis includes charged wood template fabrication, precursor infiltration, and ZnO hydrothermal growth, resulting in controlled ZnO morphologies and distributions while maintaining the hierarchical structure of the wood. Stereo-digital image correlation (stereo-DIC) investigated the relationship between deformation and piezoelectric performance, which revealed the homogeneous distribution of multilayered ZnO enhance piezoelectric performance. The output voltage of wood/ZnO was 1.5 V under periodic mechanical compression (8–10 N) for 300 cycles, while the output current was 2.91 nA. The scalable synthesis strategy and piezoelectric performance are significant for the design of advanced wood nanocomposites for sustainable and efficient energy conversion systems.

  • 12.
    Huang, Shuo
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Li, Wei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Li, Xiaoqing
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Schönecker, Stephan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Bergqvist, Lars
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Holmström, E.
    Varga, L. K.
    Vitos, Levente
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. Wigner Research Centre for Physics, Hungary; Uppsala University, Sweden.
    Mechanism of magnetic transition in FeCrCoNi-based high entropy alloys2016In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 103, p. 71-74Article in journal (Refereed)
    Abstract [en]

    First-principles alloy theory and Monte-Carlo simulations are performed to investigate the magnetic properties of FeCrCoNiAlx high entropy alloys. Results show that face-centered-cubic (fcc) and body-centered-cubic (bcc) structures possess significantly different magnetic behaviors uncovering that the alloy's Curie temperature is controlled by the stability of the Al-induced single phase or fcc-bcc dual-phase. We show that the appearance of the bcc phase with increasing Al content brings about the observed transition from the paramagnetic state for FeCrCoNi to the ferromagnetic state for FeCrCoNiAl at room-temperature. Similar mechanism is predicted to give rise to room-temperature ferromagnetism in FeCrCoNiGa high entropy alloy.

  • 13.
    Ioannidou, Chrysoula
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    König, Hans-Henrik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    Semjatov, Nick
    Friedrich Alexander Univ Erlangen Nurnberg FAU, Chair Mat Sci & Engn Met, Martensstr 5, D-91058 Erlangen, Germany..
    Ackelid, Ulf
    Freemelt AB, Bergfotsgatan 5A, SE-43135 Mölndal, Sweden..
    Staron, Peter
    Helmholtz Zentrum Hereon, Inst Mat Phys, Max Planck Str 1, D-21502 Geesthacht, Germany..
    Koerner, Carolin
    Friedrich Alexander Univ Erlangen Nurnberg FAU, Chair Mat Sci & Engn Met, Martensstr 5, D-91058 Erlangen, Germany..
    Hedström, Peter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    Lindwall, Greta
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    In-situ synchrotron X-ray analysis of metal Additive Manufacturing: Current state, opportunities and challenges2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 219, p. 110790-, article id 110790Article in journal (Refereed)
    Abstract [en]

    Additive Manufacturing (AM) is becoming an important technology for manufacturing of metallic materials. Laser-Powder Bed Fusion (L-PBF), Electron beam-Powder Bed Fusion (E-PBF) and Directed Energy Deposition (DED) have attracted significant interest from both the scientific community and the industry since these technologies offer great manufacturing opportunities for niche applications and complex geometries. Understanding the physics behind the complex and dynamic phenomena occurring during these processes is essential for overcoming the barriers that constrain the metal AM development. Insitu synchrotron X-ray characterization is suitable for investigating the microstructure evolution during processing and provides new profound insights. Here, we provide an overview of the research on metal PBF and DED using in-situ synchrotron X-ray imaging, diffraction and small-angle scattering, highlighting the state of the art, the instrumentation, the challenges and the gaps in knowledge that need to be filled. We aim at presenting a scientific roadmap for in-situ synchrotron analysis of metal PBF and DED where future challenges in instrumentation such as the development of experimental stations, sample environments and detectors as well as the need for further application oriented research are included.

  • 14. Jadhav, Suraj Dinkar
    et al.
    Dhekne, Pushkar Prakash
    Brodu, Etienne
    Van Hooreweder, Brecht
    Dadbakhsh, Sasan
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Manufacturing and Metrology Systems. KU Leuven, Department of Mechanical Engineering, & Member of Flanders Make, Celestijnenlaan 300, B-3001 Heverlee, Belgium.
    Kruth, Jean-Pierre
    Van Humbeeck, Jan
    Vanmeensel, Kim
    Laser powder bed fusion additive manufacturing of highly conductive parts made of optically absorptive carburized CuCr1 powder2021In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 198Article in journal (Refereed)
    Abstract [en]

    Fabrication of fully dense and highly conductive copper alloy parts via laser-based additive manufacturing (L-AM) is challenging due to the high optical reflectivity of copper at λ = 1060 – 1080 nm and high thermal conductivity. To overcome this, the use of optically absorptive surface-modified copper powders is being evaluated in the laser powder bed fusion (LPBF) process. Although the surface-modified powders exhibit high optical absorption at room temperature, not all of them allow the fabrication of fully dense parts at a laser power below 500 W. Accordingly, this article proposes the use of optically absorptive carburized CuCr1 powder for the consistent fabrication of copper parts. Moreover, a densification mechanism of parts is discussed to explain the distinct LPBF processing behavior of different surface-modified powders, such as carburized CuCr1 and carbon mixed CuCr1 powders, albeit having similar room temperature optical absorption. This investigation clearly outlines the advantage of a firmly bonded modified layer present on the surface of the carburized CuCr1 powder over a loosely attached carbon nanoparticle layer present in the carbon-mixed CuCr1 powder. Apart from the successful fabrication of CuCr1 parts, fabricated parts are subjected to two different post-heat treatments, and it is shown that the final properties can be customized by applying tailored post-heat treatments.

  • 15.
    Jungstedt, Erik
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Da Costa, Marcus Vinícius Tavares
    Karlstad University, Department of Engineering and Chemical Sciences, Karlstad, Sweden.
    Östlund, Sören
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Fracture toughness of wood and transparent wood biocomposites in the toughest LT-direction2023In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 231, article id 112058Article in journal (Refereed)
    Abstract [en]

    Fracture toughness and mechanisms of crack growth are characterized for transparent wood polymer biocomposites and compared to native wood, with the crack normal to the fiber direction (LT fracture plane). Side-grooved specimen geometries generated pure mode I crack growth, whereas previous investigations commonly report 90° crack path deflection. Crack growth micromechanisms were analyzed by experimental fracture tests and in-situ microscopy observations. Large damage zones around the crack tip with fiber bundle bridging and pull-out were observed in the crack wake, justifying more advanced cohesive zone modeling suitable for composite materials design. The polymer matrix resulted in much higher fracture energy of the biocomposites compared to native wood due to increased local cohesive strength. This strength increased from the polymer contribution and more homogeneous stress distribution in the wood fibers.

  • 16.
    Lamelas, Victor
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Bonvalet Rolland, Manon
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Univ Lille, Cent Lille, CNRS, INRAe,UMET,Unite Mat & Transformat,UMR 8207, F-59000 Lille, France..
    Walbruhl, M.
    QuesTek AB, Rasundavagen 18, S-16967 Solna, Sweden..
    Borgenstam, Annika
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Modelling the formation of detrimental phases in cemented carbides2023In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 228, p. 111823-, article id 111823Article in journal (Refereed)
    Abstract [en]

    Integrated Computational Materials Engineering (ICME) has proved to be an efficient tool for understand-ing the process-structure-property relationships and helping us to design materials. For instance, in cemented carbides manufacturing, one of the most critical parameters is the C-window. It is defined as the C content range for which phases detrimental to the mechanical properties are avoided. This pro-cessing window has been traditionally defined using applied thermodynamics methods. However, the deviation between equilibrium calculations and real manufacturing conditions requires big additional empirical efforts to precisely define the C-window. In this work, an ICME-based approach is proposed to redefine the processability limits of cemented carbides taking the cooling rate and the material's initial powder size into consideration. The method relies on the interactive coupling of several adapted models and tools, to not only set the processability boundaries, but also to study the complex mechanisms inter-play happening along microstructural evolution. A better understanding of these underlaying mecha-nisms leads to new inputs that can be used in the design of cemented carbides. In this regard, it is observed that faster cooling rates or coarser WC grades could be effectively used to prevent nucleation of the detrimental phases enlarging the C-window towards lower C contents. 

  • 17.
    Larsson, Per-Lennart
    et al.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    Blanchard, Pierre
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
    On the invariance of hardness at sharp indention of materials with general biaxial residual stress fields2013In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 52, p. 602-608Article in journal (Refereed)
    Abstract [en]

    In recent years, the influence from residual surface stresses on the global indentation properties, i.e. hardness and size of the contact area, have been studied quite frequently. The investigations presented have been based on experimental, theoretical and numerical methods and for one thing, the invariance of hardness in the case of residual equi-biaxial surface stresses, has been well-established. In the more general case, when the principal surface stresses are not necessarily equi-biaxial, corresponding results are more scattered and it is therefore the aim of the present study to remedy this shortcoming. In doing so, the problem is presently attacked using numerical methods and in particular the finite element method (FEM) is relied upon. Classical Mises elastoplastic material behavior is assumed throughout the investigation which is restricted, for clarity but not for necessity, to sharp cone indentation. The results confirm the invariance of hardness also for general stress fields when the deformation in the contact region is dominated by plastic deformation.

  • 18.
    Li, Xiaojie
    et al.
    Dalian Univ Technol, Minist Educ, Key Lab Mat Modificat Laser Electron & Ion Beams, Dalian 116024, Peoples R China.;KTH Royal Inst Technol, Dept Mat Sci & Engn, Appl Mat Phys, SE-10044 Stockholm, Sweden..
    Li, Xiaoqing
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Schönecker, Stephan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Li, Ruihuan
    Changzhou Vocat Inst Mechatron Technol, Inst Mold Technol, Changzhou 213164, Peoples R China..
    Zhao, Jijun
    Dalian Univ Technol, Minist Educ, Key Lab Mat Modificat Laser Electron & Ion Beams, Dalian 116024, Peoples R China..
    Vitos, Levente
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. Uppsala Univ, Div Mat Theory, Dept Phys & Astron, Box 516, SE-75120 Uppsala, Sweden.;Res Inst Solid State Phys & Opt, POB 49, H-1525 Budapest, Hungary..
    Understanding the mechanical properties of reduced activation steels2018In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 146, p. 260-272Article in journal (Refereed)
    Abstract [en]

    Reduced activation ferritic/martensitic (RAFM) steels are structural materials with potential application in Generation-IV fission and fusion reactors. We use density-functional theory to scrutinize the micro-mechanical properties of the main alloy phases of three RAFM steels based on the body-centered cubic FeCrWVMn solid solution. We assess the lattice parameters and elastic properties of ferromagnetic alpha-Fe and Fe91Cr9, which are the main building blocks of the RAFM steels, and present a detailed analysis of the calculated alloying effects of V, Cr, Mn, and W on the mechanical properties of Fe91Cr9. The composition dependence of the elastic parameters is decomposed into electronic and volumetric contributions and studied for alloying levels that cover the typical intervals in RAFM steels. A linear superposition of the individual solute effects on the properties of Fe91Cr9 is shown to provide an excellent approximation for the ab initio values obtained for the RAFM steels. The intrinsic ductility is evaluated through Rice's phenomenological theory using the surface and unstable stacking fault energies, and the predictions are contrasted with those obtained by empirical criteria. Alloying with V or W is found to enhance the ductility, whereas additional Cr or Mn turns the RAFM base alloys more brittle.

  • 19.
    Li, Xiaojie
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties. Taizhou Univ, Dept Phys, Taizhou 318000, Peoples R China..
    Schönecker, Stephan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Li, Xiaoqing
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    Zhao, Jijun
    Dalian Univ Technol, Key Lab Mat Modificat Laser Electron & Ion Beams, Minist Educ, Dalian 116024, Peoples R China..
    Vitos, Levente
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Dept Phys & Astron, Div Mat Theory, Box 516, SE-75120 Uppsala, Sweden.;Res Inst Solid State Phys & Opt, POB 49, H-1525 Budapest, Hungary..
    The influence of temperature on the elastic properties of body-centered cubic reduced activation steels2021In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 197, article id 109282Article in journal (Refereed)
    Abstract [en]

    A first-principles based modeling approach to the effect of temperature on the isothermal single-crystal and polycrystalline elastic parameters of Fe-rich solid solutions is reported. The approach integrates alloy theory for chemical and magnetic disorders with accessible experimental data for the equilibrium volume and ferromagnetic phase transition, and is adopted to predict the temperature-dependent elastic parameters of the body-centered cubic phase of three reduced activation steels, CLAM/CLF-1, F82H, EUROFER97, considered as high-temperature material in power reactors. The predictions are assessed based on available experimental data for a reduced activation steel and both experimental and theoretical data for pure Fe. Alloying effects on the elastic constants relative to pure Fe are found to differ in the magnetically ordered and disordered phases. Contributions due to loss of long-range magnetic order, volume expansion, and entropy are important in determining the temperature dependence of the elastic parameters in all investigated materials. A previously reported, peculiar magneto-volume phenomenon on the equation of state in pure Fe is gradually removed by alloying and magnetic disordering, which requires particular attention when describing the thermo-chemical effects derived from the equation of state in Fe-rich solid solutions.

  • 20.
    Ling, Senlin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering. Key Laboratory of Road and Traffic Engineering of Ministry of Education, Tongji University, Shanghai 200092, PR China.
    Elaguine, Denis
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Partl, Manfred N.
    PaRRC Partl Road Research Consulting, Oeschgen, Switzerland.
    Sun, Daquan
    Key Laboratory of Road and Traffic Engineering of Ministry of Education, Tongji University, Shanghai 200092, PR China.
    Fadil, Hassan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Predicting the mechanical properties of semi-flexible pavement material with micromechanical modeling2024In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 239, article id 112802Article in journal (Refereed)
    Abstract [en]

    Semi-flexible pavement (SFP) material is a composite comprising cement, coarse aggregates and asphalt mortar, which has complex mechanical properties. Traditional experimental methods struggle to accurately quantify the effect of each phase and their interfaces on the SFP's mechanical properties. Micromechanical modelling based on finite element method offers a promising solution. In this study, a new micromechanical model for SFP is proposed, idealizing the material by representative volume elements. SFP mesostructure is represented as a simplified five element composite consisting of cement, asphalt mortar, aggregate, pore and cement-asphalt mortar interface. Periodic boundary conditions are used to simulate an infinite repetitive structure within a finite computational domain. The resulting model allows evaluating the stiffness and damage resistance of SFP in a computationally efficient manner. This model is utilized to explore the mechanical properties of SFPs and the results are compared with the experimental findings. The results show that the model captures the uniaxial compressive strength and stiffness for all materials examined. The model is further used to evaluate the effect of properties of individual elements of SFP on its stiffness and strength. The feasibility of using the proposed modelling approach to optimize the material design of SFP is discussed.

  • 21.
    Linvill, Eric
    et al.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.). KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Larsson, Per A.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Östlund, Sören
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.). KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center BiMaC Innovation.
    Advanced three-dimensional paper structures: Mechanical characterization and forming of sheets made from modified cellulose fibers2017In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 128, p. 231-240Article in journal (Refereed)
    Abstract [en]

    Cellulose partially converted to dialcohol cellulose has been identified as a potential breakthrough material for the production of bio-based, complex, double-curved surfaces due to its extensive strain-at-break characteristics (reaching as great as 80% in tensile loading). Tensile testing of handsheets made from modified cellulose fibers was conducted from 50 to 90% relative humidity (RH) and from 23 to 150 °C. Strain-at-break of the handsheets ranged from 35 to 80% over this humidity and temperature range, which is significantly greater than typical cellulose-based materials. The combined effect of moisture and temperature was further investigated by dynamic mechanical thermal analysis, which was utilized to determine the glass-transition temperature of the handsheets as a function of relative humidity. Based on the tensile test results and verified by the three-dimensional (3-D) forming and simulation, a forming limit diagram (strain-based failure surface which describes and illustrates the formability of the material) for the handsheets was generated. This forming limit illustrates significant extent to which this bio-based material can be 3-D formed into advanced structures. Furthermore, temperature was identified as the best, quickest, and most controllable method of improving extensibility of this material during 3-D forming.

  • 22.
    Liu, Dachuan
    et al.
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Dong, Li
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Wang, Huan
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Bai, Jianzhong
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Shi, Jiaxu
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Chen, Weicheng
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Yan, Hongji
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience. KTH, Centres, Center for the Advancement of Integrated Medical and Engineering Sciences, AIMES. Department of Medical Cell Biology, Uppsala University, 75323 Uppsala, Sweden .
    Li, Bin
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Sun, Heng
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Chen, Song
    Orthopedic Institute, Department of Orthopedic Surgery, The First Affiliated Hospital, School of Biology & Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu 215006, China, Jiangsu.
    Amorphous iron-calcium phosphate-mediated biomineralized scaffolds for vascularized bone regeneration2023In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 235, article id 112413Article in journal (Refereed)
    Abstract [en]

    Construction of organic–inorganic composites similar to natural bone in terms of structure and composition has attracted extensive attention. However, the clinical applications of these composites are limited due to the insufficient osteogenic and mechanical properties. In nature, the presence of amorphous iron-calcium phosphate (Fe-ACP) strengthens the mechanical properties of some biominerals, and our previous study has revealed its synthetic route and in vitro osteogenic properties. However, the potential role of Fe-ACP on biomineralization and constructing biomimetic scaffolds for bone regeneration has not been studied. Herein, a biomimetic scaffold with good osteogenic property was fabricated based on the mineralization of Fe-ACP, with the assistance of ice-templated freeze-casting. The in vitro study showed that the mineralized scaffolds possessed favorable biocompatibility and osteogenic property. Moreover, the scaffolds promoted cell chemotaxis and angiogenic property by upregulating the hypoxia inducible factor-1α (HIF-1α). In vivo experiment demonstrated potent early osteogenesis along with angiogenesis and ultimately promoted bone regeneration. Overall, the mineralized scaffold mediated by Fe-ACP precursors provide a unique platform to enhance bone tissue repair.

  • 23.
    Liu, Hailong
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Ahlinder, Astrid
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Yassin, M. A.
    Finne Wistrand, Anna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Gasser, T. Christian
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Computational and experimental characterization of 3D-printed PCL structures toward the design of soft biological tissue scaffolds2020In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 188, article id 108488Article in journal (Refereed)
    Abstract [en]

    Degradable porous polymeric structures are attractive candidates for biological tissue scaffolds, and adequate mechanical, transport, chemical and biological properties determine their functionality. Aside from the properties of polymer-based materials, the scaffold's meso-structure controls its elasticity at the organ length-scale. This study investigated the effect of the meso-structure on scaffolds' mechanical and transport properties using finite element analysis (FEA) and computational fluid dynamics (CFD). A number of poly (ε-caprolactone) (PCL) - based scaffolds were 3D printed, analyzed by microcomputed tomography (micro-CT) and mechanically tested. We found that the gradient (G) and gradient and staggered (GS) meso-structure designs led to a higher scaffold permeability, a more homogeneous flow inside the scaffold, and a lower wall shear stress (WSS) in comparison with the basic (B) meso-structure design. The GS design resulted in scaffold stiffness as low as 1.07/0.97 MPa under compression/tension, figures that are comparative with several soft tissues. Image processing of micro-CT data demonstrated that the imposed meso-structures could have been adequately realized through 3D printing, and experimental testing validated FEA analysis. Our results suggest that the properties of 3D-printed PCL-based scaffolds can be tuned via meso-structures toward soft tissue engineering applications. The biological function of designed scaffolds should be further explored in-situ studies.

  • 24.
    Lv, Yezhe
    et al.
    School of Materials Science and Engineering, Zhengzhou University, PR China.
    Sun, Yufu
    School of Materials Science and Engineering, Zhengzhou University, PR China.
    Zhao, Jingyu
    Yu, Guangwen
    School of Materials Science and Engineering, Zhengzhou University, PR China.
    Shen, Jingjie
    School of Materials Science and Engineering, Zhengzhou University, PR China.
    Hu, Sumeng
    School of Materials Science and Engineering, Zhengzhou University, PR China.
    Effect of tungsten on microstructure and properties of high chromium cast iron2012In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 39, p. 303-308Article in journal (Refereed)
    Abstract [en]

    In this study, effect of tungsten on microstructure and properties of high chromium cast iron was investigated.The experimental results indicated that tungsten distributed uniformly in the matrix and carbides.W carbides are composed of WC1x, W6C2.54 and CW3 and W2C. With the increase of tungstencontent, bulk hardness and matrix microhardness both increased gradually and reached the peak at62.62HRC and 913HV, respectively. All of the tungsten-containing alloys performed better than tungsten-freealloys in impact tests and alloys containing 1.03 wt% W showed the highest impact toughness at8.23 J cm2. Tungsten considerably improved the performance of high chromium cast iron on wearresistance and alloys containing 1.03 wt%Wincreased 205% compared to tungsten-free alloys. Therefore,tungsten can be used as an alloying element to increase the hardness and wear resistance without scarifyingimpact toughness in high chromium cast iron. Alloys containing 1.03 wt% tungsten showed theoptimum properties.

  • 25.
    Mao, Huina
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Rumpler, Romain
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Gaborit, Mathieu
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Kennedy, John
    Trinity College Dublin, Ireland.
    O'Connor, Daragh
    Trinity College, Dublin.
    Trimble, Daniel
    Trinity College Dublin, Ireland.
    Rice, Henry
    Trinity College Dublin, Ireland.
    Twist, tilt and stretch: From isometric Kelvin cells to anisotropic cellular materials2020In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 193, article id 108855Article in journal (Refereed)
    Abstract [en]

    Simple geometric distortions applied to the isometric Kelvin cell structures, (the tetrakaidecahedron), are shown to result in equivalent materials with anisotropic Hooke's tensors. The equivalent material models are estimated using a recently published inversion method where the 21 independent elastic constants of the Hooke's tensor are identified. In these cell geometries, some of the faces of the Kelvin cell have been twisted and/or tilted. Numerical experiments suggest that the equivalent material models of the distorted cells exhibit variations in compression, shearing, shear-compression and shear-shear coupling moduli, which are shown to be continuous functions of the degree of twist and tilt applied. When twist and tilt are combined, it is demonstrated that full anisotropy in the elastic properties may be generated. A rotational symmetry without symmetry planes, but having either a tetragonal or a monoclinic elastic symmetry is discussed. Four cell geometries, one isometric and three distorted, were manufactured using masked stereolithography 3D printing technology and measured in a laboratory compression set-up. Results from numerical simulations are compared to the experimental in terms of the compressive modulus.

    Download full text (pdf)
    fulltext
  • 26.
    Medina, Leon Zendejas
    et al.
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    da Costa, Marcus V. Tavares
    Uppsala Univ, Dept Mat Sci & Engn, Div Appl Mech, Box 534, SE-75121 Uppsala, Sweden..
    Paschalidou, E. Maria
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    Lindwall, Greta
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Riekehr, Lars
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    Korvela, Marcus
    Uppsala Univ, Dept Chem BMC, Analyt Chem, Box 599, SE-75124 Uppsala, Sweden..
    Fritze, Stefan
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    Kolozsvari, Szilard
    Plansee Composite Mat GmbH, Siebenburgerstr 23, DE-86983 Lechbruck, Germany..
    Gamstedt, E. Kristofer
    Uppsala Univ, Dept Mat Sci & Engn, Div Appl Mech, Box 534, SE-75121 Uppsala, Sweden..
    Nyholm, Leif
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    Jansoon, Ulf
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    Enhancing corrosion resistance, hardness, and crack resistance in magnetron sputtered high entropy CoCrFeMnNi coatings by adding carbon2021In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 205, article id 109711Article in journal (Refereed)
    Abstract [en]

    This study explores carbon addition as a materials design approach for simultaneously improving the hardness, crack resistance, and corrosion resistance of high entropy thin films. CoCrFeMnNi was selected as a starting point, due to its high concentration of weak carbide formers. The suppression of carbides is crucial to the approach, as carbide formation can decrease both ductility and corrosion resistance. Films with 0, 6, and 11 at.% C were deposited by magnetron co-sputtering, using a graphite target and a sintered compound target. The samples with 0 at.% C crystallized with a mixture of a cubic closed packed (ccp) phase and the intermetallic chi-phase. With 6 and 11 at.% C, the films were amorphous and homogenous down to the nm-scale. The hardness of the films increased from 8 GPa in the carbon-free film to 16 GPa in the film with 11 at.% C. Furthermore, the carbon significantly improved the crack resistance as shown in fragmentation tests, where the crack density was strongly reduced. The changes in mechanical properties were primarily attributed to the shift from crystalline to amorphous. Lastly, the carbon improved the corrosion resistance by a progressive lowering of the corrosion current and the passive current with increasing carbon concentration.

  • 27.
    Mehboob, Ali
    et al.
    Khalifa Univ, Adv Digital & Addit Mfg Ctr, Abu Dhabi, U Arab Emirates..
    Mehboob, Hassan
    Prince Sultan Univ, Coll Engn, Dept Engn Management, Riyadh 11586, Saudi Arabia..
    Ouldyerou, Abdelhak
    Prince Sultan Univ, Coll Engn, Dept Engn Management, Riyadh 11586, Saudi Arabia.;Univ Mascara, Dept Mech Engn, Mascara, Algeria..
    Barsoum, Imad
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Advanced Digital & Additive Manufacturing Center, Khalifa University, Abu Dhabi, United Arab Emirates; Department of Mechanical and Nuclear Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
    Computational biomechanical analysis of Ti-6Al-4V porous bone plates for lower limb fractures2024In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 240, article id 112842Article in journal (Refereed)
    Abstract [en]

    The current study investigates the biomechanical performance of porous bone plates augmented with three different cellular lattice structures, e.g., body-centered cube (BCC), simple cube (SC), and the superposition of simple and body-centered cube (SC-BCC) structures. The SC-BCC cellular structures, exhibiting improved torsional, compression, and bending stiffness, were strategically integrated into the bone plates. Configurations ranging from one to three rows, with porosity ranging from 30% to 90%. Increasing the number of rows and porosity maximized the interfragmentary movement at the fracture site. Specifically, SC-BCC configurations with one, two and three rows at 90% porosity demonstrated callus volume improvements of 31.33%, 42%, and 43.2%, respectively, compared with the lowest callus volume observed with SC-BCC at one row and 30% porosity. Regardless of the improved volume, callus stiffness was highest at 30% and 90% porosity levels across all cases, indicating more mature tissue formation in calluses and better physiological load support. High stresses located at 90% porosity, followed by 50% porosity, discouraged their mechanical performance. Therefore, employing 30% porosity configurations with appropriate vertical rows for desired movement is recommended for optimal biomechanical performance. However, 90% porosity may be suitable in scenarios involving minimal forces and restricted patient movement.

  • 28.
    Mu, Wangzhong
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Rahaman, Moshiour
    Rios, Felix L.
    Odqvist, Joakim
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Hedström, Peter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Predicting strain-induced martensite in austenitic steels by combining physical modelling and machine learning2021In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 197, article id 109199Article in journal (Refereed)
    Abstract [en]

    Computational materials design has made significant progress lately. However, one underexploited opportunity lies in the combination of physically based modelling and machine learning (ML). In the present work we exploit this combination for modelling of strain-induced martensitic phase transformation (SIMT) in austenitic steels. A fully predictive model for SIMT, responsible for the TRIP effect in many steels, is devised. An experimental dataset correlating SIMT with composition, temperature and strain is collected from the open literature firstly. Secondly, the Olson-Cohen model is applied to make physically based predictions on temperature and strain dependence of SIMT in order to expand the database to the final size of 16,500 entries relating the features and the target. Thirdly, ensemble ML methods are applied to model the data and the final model is validated on a holdout dataset, including also dual-phase alloys. The final model provides accurate predictions of SIMT in a temperature range from −196 to 100 °C and from 0 to 1 in strain. The model can readily be extended to consider further factors such as strain rate and stress state. Moreover, it can be used together with thermodynamic and kinetic calculations, or thermomechanical simulations, for the design of steels and components, respectively.

  • 29.
    Osinger, Barbara
    et al.
    Uppsala Univ, Dept Chem Angstrom, SE-75121 Uppsala, Sweden..
    Mao, Huahai
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Thermo Calc Software AB, Solna, Sweden..
    Fritze, Stefan
    Uppsala Univ, Dept Chem Angstrom, SE-75121 Uppsala, Sweden..
    Riekehr, Lars
    Uppsala Univ, Dept Chem Angstrom, SE-75121 Uppsala, Sweden.;Univ Antwerp, Dept Phys, Antwerp, Belgium..
    Jansson, Ulf
    Uppsala Univ, Dept Chem Angstrom, SE-75121 Uppsala, Sweden..
    Lewin, Erik
    Uppsala Univ, Dept Chem Angstrom, SE-75121 Uppsala, Sweden..
    Investigation of the phase formation in magnetron sputtered hard multicomponent (HfNbTiVZr)C coatings2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 221, article id 111002Article in journal (Refereed)
    Abstract [en]

    Multicomponent carbides have gained interest especially for ultra-high temperature applications, due to their ceramic hardness, good oxidation resistance and enhanced strength. In this study the phase forma-tion, stability and mechanical properties of (HfNbTiVZr)C multicomponent carbide coatings were inves-tigated. Phase stability was predicted by the CALPHAD (CALculation of PHAse Diagrams) methods. This revealed that the multicomponent solid solution phase is only stable at elevated temperatures, namely above 2400 degrees C. At lower temperatures a phase mixture was predicted, with a particular tendency for V to segregate. Magnetron sputtered thin films deposited at 300 degrees C exhibited a single NaCl-type multicom-ponent carbide phase, which attributes to the kinetic stabilisation of simple structures during thin film growth. Films deposited at 700 degrees C, or exposed to UHV annealing at 1000 degrees C, however, revealed the decom-position of the single-phase multicomponent carbide by partial elemental segregation and formation of additional phases. Thus, confirming the CALPHAD predictions. These results underscore the importance of explicitly considering temperature when discussing the stability of multicomponent carbide materials, as well as the applicability of CALPHAD methods for predicting phase formation and driving forces in these materials. The latter being crucial for designing materials, such as carbides, that are used in appli-cations at elevated temperatures.

  • 30. Paraskevas, Dimos
    et al.
    Dadbakhsh, Sasan
    KU Leuven, Department of Mechanical Engineering, Celestijnenlaan 300A, Heverlee, B-3001, Belgium.
    Vleugels, Jef
    Vanmeensel, Kim
    Dewulf, Wim
    Duflou, Joost R.
    Solid state recycling of pure Mg and AZ31 Mg machining chips via spark plasma sintering2016In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 109, p. 520-529Article in journal (Refereed)
    Abstract [en]

    This work investigates the applicability of spark plasma sintering (SPS) as a solid state recycling technique for magnesium alloy scrap. In this respect, machining chips from pure Mg and AZ31 Mg alloy ingots are chemically cleaned, cold compacted and SPSed directly into bulk specimens. It is found that SPS can successfully establish full densification and effective metallurgical bonding between chips without altering compositional constituents. This is attributed to the dynamic compaction during sintering as well as to the disruption of the chips' surface oxide film due to SPS electric current based joule heating. Apart from the successful consolidation, microstructural analysis of the initial Mg ingots, chips and SPS recycled material reveals that the SPS microstructure was finer than that of the original ingots due to significant deformation induced grain refinement during machining. As a result, the recycled materials had a higher compression and shear strength than that of the starting ingot material. The findings indicate that SPS is an effective alternative method for solid state recycling of magnesium alloy scrap.

  • 31.
    Poulikidou, Sofia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Jerpdal, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Björklund, Anna
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Akermo, Malin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Environmental performance of self-reinforced composites in automotive applications - Case study on a heavy truck component2016In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 103, p. 321-329Article in journal (Refereed)
    Abstract [en]

    A screening environmental life cycle analysis (LCA) of the novel self-reinforced poly(ethylene therephthalate) (SrPET) is presented in this paper. A truck exterior panel is used as case study where a concept design made by SrPET is assessed and compared to a glass fibre reinforced composite and a thermoplastic blend that are currently used for the selected component. The results showed that the SrPET panel has 25% lower environmental impact compared to the current design, with no significant life cycle trade-offs. SrPET offers possibilities for weight reduction while maintaining good mechanical properties. As the impact during use phase is expected to decrease in the future the relative importance of manufacturing and end-of-life (EOL) will increase. Thus SrPET can be considered a competitive material for replacing existing energy intense non-recyclable composites.

  • 32.
    Poulikidou, Sofia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    Schneider, Christof
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Björklund, Anna
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    Kazemahvazi, Sohrab
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Univ Cambridge, England.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Zenkert, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    A material selection approach to evaluate material substitution for minimizing the life cycle environmental impact of vehicles2015In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 83, p. 704-712Article in journal (Refereed)
    Abstract [en]

    Weight reduction is commonly adopted in vehicle design as a means for energy and emissions savings. However, selection of lightweight materials is often focused on performance characteristics, which may lead to sub optimizations of life cycle environmental impact. Therefore systematic material selection processes are needed that integrate weight optimization and environmental life cycle assessment. This paper presents such an approach and its application to design of an automotive component. Materials from the metal, hybrid and polymer families were assessed, along with a novel self-reinforced composite material that is a potential lightweight alternative to non-recyclable composites. It was shown that materials offering the highest weight saving potential offer limited life cycle environmental benefit due to energy demanding manufacturing. Selection of the preferable alternative is not a straightforward process since results may be sensitive to critical but uncertain aspects of the life cycle. Such aspects need to be evaluated to determine the actual benefits of lightweight design and to base material selection on more informed choices.

    Download full text (pdf)
    fulltext
  • 33.
    Qu, Muchao
    et al.
    School of Automobile and Transportation Engineering, Guangdong Polytechnic Normal University, Guangdong, China; Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany, Martensstr. 7.
    Luo, Ziying
    School of Automobile and Transportation Engineering, Guangdong Polytechnic Normal University, Guangdong, China.
    Chen, Hongji
    School of Automobile and Transportation Engineering, Guangdong Polytechnic Normal University, Guangdong, China.
    Qin, Yijing
    Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany, Martensstr. 7.
    Schubert, Dirk W.
    Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany, Martensstr. 7.
    Yang, Guanda
    Institute of Polymer Materials, Friedrich-Alexander-University Erlangen-Nuremberg, Martensstr. 7, 91058 Erlangen, Germany, Martensstr. 7.
    Han, Lei
    School of Automobile and Transportation Engineering, Guangdong Polytechnic Normal University, Guangdong, China.
    Nilsson, Fritjof
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials. FSCN Research Centre, Mid Sweden University, 85170 Sundsvall, Sweden.
    Strain sensing, electromagnetic interference shielding, and antimicrobial performance of triple hierarchic fabric coated with AgNWs and polydopamine2024In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 243, article id 113033Article in journal (Refereed)
    Abstract [en]

    For wearable smart textile sensors, stability, accuracy and multi-functionality are key objectives. Achieving the optimal application requires delicately balancing the crucial physical properties of strain sensors, presenting a key technological challenge. This study addresses these challenges by presenting several properties and potential applications of a triple hierarchic polymeric knitted fabric. The fabric incorporates an internal conductive network constructed with silver nanowires (AgNWs) and polydopamine (PDA) coating on its outer surface. This innovative textile successfully strikes a balance between strain sensing and electromagnetic interference shielding while concurrently exhibiting biocompatibility and antimicrobial properties. Significantly, acknowledging the susceptibility of measurements from polymer-based strain sensor materials to time drift, we introduce both a modeling approach and a novel calibration technique. This advancement facilitates the generation of stable cyclic sensing signals, even under substantial deformations of up to 80 % at a high stretching speed. Importantly, it provides a practical solution for addressing signal drift observed in flexible sensors when utilized in environments characterized by long-term and large deformations.

  • 34.
    Rehman, Hafeez Ur
    et al.
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Chen, Yujie
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Hedenqvist, Mikael S.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Pathan, Radan
    Shanghai Jiao Tong Univ, Dept Automat, Shanghai 200240, Peoples R China..
    Liu, Hezhou
    Shanghai Jiao Tong Univ, Collaborat Innovat Ctr Adv Ship & Dee Sea Explora, Shanghai 200240, Peoples R China..
    Wang, Hesheng
    Shanghai Jiao Tong Univ, Dept Automat, Shanghai 200240, Peoples R China..
    Chen, Tao
    Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China..
    Zhang, Xiaomiao
    Shanghai Gen Hosp, Songjiang Rd 650, Shanghai 201620, Peoples R China..
    Li, Hua
    Shanghai Jiao Tong Univ, Collaborat Innovat Ctr Adv Ship & Dee Sea Explora, Shanghai 200240, Peoples R China..
    High-cycle-life and high-loading copolymer network with potential application as a soft actuator2019In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 182, article id UNSP 108010Article in journal (Refereed)
    Abstract [en]

    Thermo-responsive polymer materials ate appealing in emerging fields including soft robotics, artificial muscles, and actuators. However, realising a single smart polymer material that can achieve immense strain, fast actuation, and high loading remains a challenge. We attempted to address these limitations by fabricating a thermo-responsive copolymer network structure of poly(urethane-caprolactone-siloxane). The relative concentrations of these precursors were adjusted to realise a high mechanical strength of >= 17 MPa, 100% shape fixation, and a quick shape recovery time of <= 15 s. Experimental results revealed that the soft segments largely determines the extensibility and crystallinity of the copolymer material. The thermal gradient of the soft part enables the copolymer to self-heal during shape recovery. The copolymer network was applied to a load lifting device as an artificial muscle and was able to lift 200 times its weight with a short response time of <5 s and maximum power density that was half that of mammalian skeletal muscles. With its fast actuation, high loading, and self-healing abilities, the developed therrno-activated smart copolymer material is potentially applicable to a wide range of fields such as soft robotics, biomimetic devices, and prosthetics.

  • 35.
    Schönecker, Stephan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    Li, Xiaojie
    Taizhou Univ, Dept Phys, Taizhou 318000, Zhejiang, Peoples R China..
    Wei, Daixiu
    Tohoku Univ, Inst Mat Res, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan..
    Nozaki, Shogo
    Tohoku Univ, Dept Mat Sci, 6-6-02 Aramaki Aza Aoba, Sendai, Miyagi 9808579, Japan..
    Kato, Hidemi
    Tohoku Univ, Inst Mat Res, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan..
    Vitos, Levente
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties. Wigner Res Ctr Phys, Res Inst Solid State Phys & Opt, POB 49, H-1525 Budapest, Hungary.;Uppsala Univ, Dept Phys & Astron, Div Mat Theory, Box 516, SE-75120 Uppsala, Sweden..
    Li, Xiaoqing
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    Harnessing elastic anisotropy to achieve low-modulus refractory high-entropy alloys for biomedical applications2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 215, article id 110430Article in journal (Refereed)
    Abstract [en]

    A high-priority target in the design of new metallic materials for load-bearing implant applications is the reduction of Young's modulus approximating that of cortical bone in the predominant loading direction. Here, we explore how directionally preferential bulk elastic properties of implant materials are achieved by harnessing elastic anisotropy. Specifically focusing on recently proposed biocompatible refractory high-entropy alloys (RHEAs) in the body-centered cubic structure, we conduct systematic densityfunctional theory calculations to investigate the single-crystal elastic properties of 21 Ti-containing RHEAs. Our results provide evidence that the valence electron count has a dominant influence on elastic anisotropy and crystal directions of low Young's modulus and high torsion modulus in the RHEAs. By means of modeling the orientation distribution function for crystallographic texture, we examine the effect of non-random texture on the anisotropic poly-crystalline Young's modulus and torsion modulus with varying texture sharpness. We adopt fiber textures that can result from rolling and distinct texture orientations that can form during rapid directional solidification. We discuss the potential for lowering Young's modulus in the RHEAs by using single crystals or textured aggregates. Furthermore, we prepare four of the theoretically considered alloys by arc-melting and report their lattice parameters, quasi isotropic Young's moduli, and Wickers hardnesses.

  • 36.
    Sun, Xun
    et al.
    Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
    Lu, Song
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    Xie, Ruiwen
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    An, Xianhai
    School of Aerospace, Mechanical & Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia.
    Li, Wei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Zhang, Tianlong
    Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
    Liang, Chuanxin
    Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
    Ding, Xiandong
    Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
    Wang, Yunzhi
    Department of Materials Science and Engineering, The Ohio State University, 2041 College Road, Columbus, OH 43210, USA.
    Zhang, Hualei
    Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
    Vitos, Levente
    Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Budapest H-1525, P.O. Box 49, Hungary.
    Can experiment determine the stacking fault energy of metastable alloys?2021In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 199, article id 109396Article in journal (Refereed)
    Abstract [en]

    Stacking fault energy (SFE) plays an important role in deformation mechanisms and mechanical properties of face-centered cubic (fcc) metals and alloys. In many concentrated fcc alloys, the SFEs determined from density functional theory (DFT) calculations and experimental methods are found having opposite signs. Here, we show that the negative SFE by DFT reflects the thermodynamic instability of the fcc phase relative to the hexagonal close-packed one; while the experimentally determined SFEs are restricted to be positive by the models behind the indirect measurements. We argue that the common models underlying the experimental measurements of SFE fail in metastable alloys. In various concentrated solid solutions, we demonstrate that the SFEs obtained by DFT calculations correlate well with the primary deformation mechanisms observed experimentally, showing a better resolution than the experimentally measured SFEs. Furthermore, we believe that the negative SFE is important for understanding the abnormal behaviors of partial dislocations in metastable alloys under deformation. The present work advances the fundamental understanding of SFE and its relation to plastic deformations, and sheds light on future alloy design by physical metallurgy. 

  • 37. Sun, Yufu
    et al.
    Hu, Sumeng
    Xiao, Zhiyun
    You, Sansan
    Zhao, Jingyu
    Yezhe, Lyu
    School of Materials Science and Engineering, Zhengzhou University, 97 Wenhua Road, Zhengzhou 450002, China.
    Effects of nickel on low-temperature impact toughness and corrosion resistanceof high-ductility ductile iron2012In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, ISSN 0264-1275, Vol. 41, p. 37-42Article in journal (Refereed)
    Abstract [en]

    High-ductility ductile iron was alloyed with 0–1.8 wt% Ni in this paper. The low-temperature impact toughness test and corrosion test of simulated seawater static whole-soaking were conducted to research the effect of nickel on the low-temperature impact toughness and corrosion resistance of high-ductility ductile iron. The results show that with nickel increasing, the impact toughness under low temperature ascents a great deal, and reaches the highest point with 0.71 wt% nickel addition, then descents; while the corrosion resistance has always been growing with the increasing of nickel content. Ductile iron containing 0.71 wt% nickel shows the best low-temperature impact toughness (the impact toughness values Akv of the samples reached 16.6 J at 20 C, 12.8 J at 40 C respectively) and exhibits the optimum combination properties. The presence of rust layer, which was made up of Fe3O4, played certain barrier for electrochemical reaction.

  • 38.
    Tan, Zhifei
    et al.
    Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hung Hom, Kowloon, Hong Kong, Peoples R China..
    Leng, Zhen
    Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hung Hom, Kowloon, Hong Kong, Peoples R China..
    Jiang, Jiwang
    Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hung Hom, Kowloon, Hong Kong, Peoples R China..
    Cao, Peng
    Beijing Univ Technol, Coll Architecture & Civil Engn, Beijing, Peoples R China..
    Elaguine, Denis
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Li, Gaoyang
    Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hung Hom, Kowloon, Hong Kong, Peoples R China..
    Sreeram, Anand
    Univ Texas Austin, Dept Civil Architectural & Environm Engn, Austin, TX USA..
    Numerical study of the aggregate contact effect on the complex modulus of asphalt concrete2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 213, article id 110342Article in journal (Refereed)
    Abstract [en]

    Asphalt concrete (AC) is a composite material consisting of binder, aggregates and air voids. The quantitative effect of aggregate-to-aggregate contact on the mechanical performance of AC is an important and complex issue, which has not been fully understood yet. To fill this gap, this study aims to characterize the aggregate contacts in AC and evaluate their effects on the viscoelastic behavior of AC through micromechanical finite element (FE) modeling. To this end, 3D microstructural models were generated through digital image processing (DIP) method and aggregate contacts were captured in the model via contact zone (CZ) elements. A CZ model was proposed and verified by a parametric study to identify the viscoelastic properties of CZ elements, while the viscoelastic properties of matrix phase were determined through laboratory tests. Steady-state dynamic (SSD) analysis was then conducted to investigate the macro-scale viscoelastic response of AC. It was found that the proposed modeling approach captures the measured response accurately. Accounting for aggregate contacts results in higher predicted AC dynamic moduli and lower phase angles, thus improving the agreement between modeling and experimental results. The numerical model developed in this study provides a promising approach for investigating the effect of aggregate contacts on the mechanical performance of AC.

  • 39.
    Tan, Zhifei
    et al.
    Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Center for Resources Engineering Towards Carbon Neutrality, The Hong Kong Polytechnic University, Hong Kong, China.
    Yang, Bin
    Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Center for Resources Engineering Towards Carbon Neutrality, The Hong Kong Polytechnic University, Hong Kong, China.
    Leng, Zhen
    Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Center for Resources Engineering Towards Carbon Neutrality, The Hong Kong Polytechnic University, Hong Kong, China.
    Jelagin, Denis
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Cao, Peng
    College of Architecture and Civil Engineering, Beijing University of Technology, Beijing, China.
    Li, Rui
    Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Center for Resources Engineering Towards Carbon Neutrality, The Hong Kong Polytechnic University, Hong Kong, China; National & Local Joint Engineering Research Center of Transportation and Civil Engineering Materials, Chongqing Jiaotong University, Chongqing, China.
    Zou, Fuliao
    Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China; Research Center for Resources Engineering Towards Carbon Neutrality, The Hong Kong Polytechnic University, Hong Kong, China.
    Multiscale characterization and modeling of aggregate contact effects on asphalt concrete's tension–compression asymmetry2023In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 232, article id 112092Article in journal (Refereed)
    Abstract [en]

    Asphalt concrete (AC) exhibits significant tension–compression (TC) asymmetry and aggregate contacts can be one of the critical contributors to this behavior. Nevertheless, the underlying mechanisms are still unclear, and there has been no study to quantify this behavior. To fill the research gap, multiscale characterization and modeling on AC were performed in this study. At the microscale level, nanoindentation tests were conducted to characterize the aggregate contact characteristics in the contact region (CR). The CR was found to have a sandwich-like structure consisting of two interfacial layers, large filler particles, and asphalt mastic. Accordingly, micromechanical models of CR were developed to predict its mechanical behavior in tension and compresison (T&C). The modeling results showed that aggregate contacts significantly increase the compressive modulus, leading to the substantial TC asymmetry of CR. The predicted viscoelastic properties of CR were further applied to the developed mesostructural model of AC. The predicted master curves in T&C showed significant asymmetry and quantitatively agreed with the experimental ones, demonstrating the effectiveness of the adopted modeling approaches. This study is the first study to quantify the asymmetric performance of AC. The outcomes can be applied to evaluate AC's TC asymmetry effects on pavement performance.

  • 40.
    Tavares da Costa, Marcus Vinicius
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Li, Lengwan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Berglund, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Biocomposites.
    Fracture properties of thin brittle MTM clay coating on ductile HEC polymer substrate2023In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 230, article id 111947Article in journal (Refereed)
    Abstract [en]

    Thin clay coatings can be deposited from water dispersions for the purpose of improved gas barrier properties and fire retardancy of polymeric materials. Mechanical properties of the coatings are difficult to assess, since they are very thin (≈1µm). In-situ tests using a micro tensile stage in a scanning electron microscope reveal a thickness-dependent microcracking mechanism, and Weibull parameters for coating fracture are extracted. Complex fracture events are identified, related to a weak clay coating-polymer substrate interface. A micromechanical finite element formulation provides values of 5 MPa for interfacial shear strength and 1 J/m2 for interfacial fracture toughness. From the multiple cracking behavior of the clay coating, a clay strength ≈ 225 MPa is estimated by the Weibull strength parameter from fragmentation diagrams. The method may be extended to other combinations of brittle coating-ductile substrates.

  • 41.
    Uddin, Mohammed Ayaz
    et al.
    Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE.
    Barsoum, Imad
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE.
    Kumar, S.
    James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
    Schiffer, Andreas
    Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi, UAE.
    Enhancing compressive performance in 3D printed pyramidal lattice structures with geometrically tailored I-shaped struts2024In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 237, article id 112524Article in journal (Refereed)
    Abstract [en]

    This study examines the compressive response of geometrically tailored pyramidal lattice structures composed of struts with I-shaped cross-sections. Geometrically tailored pyramidal lattices with micro-scale features are 3D printed using the Digital Light Processing (DLP) technique, and their effective elastic modulus, collapse strength and energy absorption capacity are experimentally evaluated under quasi-static compressive loading. Furthermore, detailed non-linear finite element (FE) calculations are performed to examine underlying collapse mechanisms and explore the vast design space offered by the proposed geometrical tailoring scheme. Both the experimental and numerical results show that the geometrically tailored lattice structures outperform conventional pyramidal lattices of equal weight in terms of elastic modulus (+24 %), collapse strength (+21 %) and energy absorption (+68 %). Notably, these strength improvements are attributed to lateral buckling that prompts the I-shaped struts to bend sideways during collapse. Specific cross-sectional designs demonstrate remarkable enhancements in strength and energy absorption, reaching up to 93 % and 161 %, respectively, differentiating them significantly from conventional designs.

  • 42.
    Van Tran, Khanh
    et al.
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany.;Tech Univ Berlin, Str 17 Juni 135, D-10623 Berlin, Germany.;Thuyloi Univ, 175 Tay Son, Hanoi, Vietnam..
    Woracek, Robin
    European Spallat Source ESS ERIC, SE-22100 Lund, Sweden..
    Kardjilov, Nikolay
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany..
    Markoetter, Henning
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany.;Bundesanstalt Mat Forsch & Prufung, Unter Eichen 87, D-12205 Berlin, Germany..
    Abou-Ras, Daniel
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany..
    Puplampu, Stephen
    Univ Tennessee, Knoxville, TN 37996 USA..
    Foerster, Christiane
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany..
    Penumadu, Dayakar
    Univ Tennessee, Knoxville, TN 37996 USA..
    Dahlberg, Carl F. O.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Solid Mechanics.
    Banhart, John
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany.;Tech Univ Berlin, Str 17 Juni 135, D-10623 Berlin, Germany..
    Manke, Ingo
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany.;Tech Univ Berlin, Str 17 Juni 135, D-10623 Berlin, Germany..
    Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 222, article id 111037Article in journal (Refereed)
    Abstract [en]

    Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional character-ization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure charac-terization methods towards the meso-and macroscale.

  • 43. Velea, M. N.
    et al.
    Schneider, Christof
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Swerea.
    Lache, S.
    Second order hierarchical sandwich structure made of self-reinforced polymers by means of a continuous folding process2016In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 102, p. 313-320Article in journal (Refereed)
    Abstract [en]

    One typical way to obtain higher stiffness and strength to weight ratios within structural applications is to use sandwich structures containing lightweight cellular cores. In this study a novel second order hierarchical sandwich structure and its manufacturing principle are described. The whole hierarchical structure is made of a fully recyclable material - different forms of poly-ethylene terephthalate (PET): PET matrix, reinforced with PET fibres (Self reinforced - SrPET) and PET foam resulting in a recyclable structure. The manufacturing path is developed such that it can be implemented within a continuous production line. Out-of-plane compression test are carried out in order to determine the stiffness and strength properties of the proposed structure. An analytical model is developed for evaluating the out-of-plane stiffness and strength properties and used for investigating the influence of the geometric parameters on the structural performance of the proposed hierarchical sandwich structure. (C) 2016 Elsevier Ltd. All rights reserved.

  • 44.
    Walbrühl, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Linder, David
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH, Royal Inst Technol, Dept Mat Sci & Engn, Unit Struct, SE-10044 Stockholm, Sweden..
    Bonvalet, Manon
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. KTH, Royal Inst Technol, Dept Mat Sci & Engn, Unit Struct, SE-10044 Stockholm, Sweden..
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Borgenstam, Annika
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    ICME guided property design: Room temperature hardness in cemented carbides2019In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 161, p. 35-43Article in journal (Refereed)
    Abstract [en]

    The potential change in EU regulations may affect the traditional W-C-Co based cemented carbides industry and a methodology is required to accelerate the materials development with alternative binders. This work presents the ICME (Integrated Computational Materials Engineering) framework and the improved models that will enable tailor-made materials design of cemented carbides. The cemented carbide hardness is one of the key properties of the composites and here its close relation to the binder composition is in focus. Modeling the influence of alternative binder materials on the hardness of cemented carbides offers a way to optimize the composite properties of prospective binder candidates virtually, thereby reducing the development time and costs drastically compared to a classical trial-and-error method. The outline of a genetic algorithm is presented and the integration of the required models and tools, that are, or will become, available within this ICME framework, are presented.

  • 45.
    Wang, Tianxiang
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Wang, Yue
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Crocetti, Roberto
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Wålinder, Magnus
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Materials.
    Influence of face grain angle, size, and moisture content on the edgewise bending strength and stiffness of birch plywood2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 223, p. 111227-, article id 111227Article in journal (Refereed)
    Abstract [en]

    Birch plywood exhibits outstanding mechanical properties with regards to tensile, compressive, and shear behaviors, making this engineered wood product promising in timber connection applications. However, the edgewise bending strength and stiffness, which are often critical for the design of gusset plates, have not been investigated thoroughly. Moreover, in engineering applications, the size and moisture content of the plywood plate are in general very different from those adopted in laboratory testing according to current standards. This paper aims to investigate the influence of face grain angle, size, and moisture content on the edgewise bending strength and stiffness of birch plywood. In total, 288 birch plywood specimens were tested in three-point bending at five different face grain angles to the beam longitudinal axis (from 0 degrees (parallel) to 90 degrees (perpendicular), with an angle step of 22.5 degrees), with four different sizes (with the nominal depth of 20 mm, 30 mm, 40 mm, and 50 mm) and three different moisture contents (7.2 %, 11.9 %, and 21.8 %). Analytical and numerical models, both taking non-linear elasto-plastic compressive behaviors into account, were developed for the prediction of the ultimate moment capacity based on different failure definitions. Lastly, the relationships between the bending strength and elastic modulus were analyzed.

  • 46.
    Wang, Wei
    et al.
    Northeast Elect Power Univ, Dept Chem Engn, Jilin 132012, Peoples R China..
    Mu, Wangzhong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Northeastern Univ, Key Lab Electromagnet Proc Mat.
    Wei, Dawei
    Northeast Elect Power Univ, Dept Chem Engn, Jilin 132012, Peoples R China.;Univ Sci & Technol Beijing, Dept Mat Sci & Engn, Beijing 100083, Peoples R China..
    Wu, Hongliu
    Northeast Elect Power Univ, Dept Chem Engn, Jilin 132012, Peoples R China..
    Yu, Libo
    Northeast Elect Power Univ, Dept Chem Engn, Jilin 132012, Peoples R China..
    Jonsson, Torbjoern
    Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296, Gothengurg, Sweden..
    Larsson, Henrik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Thermo Calc Software, Rasundavagen 18, S-16767 Solna, Sweden..
    Mao, Huahai
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Thermo Calc Software, Rasundavagen 18, S-16767 Solna, Sweden..
    High corrosion resistance duplex fcc plus hcp cobalt based entropic alloys: An experimental and theoretical investigation2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 223, p. 111166-, article id 111166Article in journal (Refereed)
    Abstract [en]

    A series of duplex fcc + hcp Co-based entropic alloys are being discovered as a new category of entropic alloys with outstanding mechanical properties, especially to overcome a typical mechanical trade-off between strength and ductility. In this work, CALPHAD-based (CALculation of PHAse Diagram) thermo-dynamic calculations were performed to facilitate alloy design and to understand corrosion behaviors. The kinetics of the electrochemical corrosion for designed alloys in typical aggressive anion Cl-was inves-tigated by electrochemical tests, including open circuit potential (OCP), polarization and cyclic polariza-tion curves, and electrochemical impedance spectroscopy (EIS). The valence state and the surface morphologies of the passive films were investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). High corrosion resistance materials with high strength and ductility per-formances were discovered in the present work. Except for Ni-oxides, various spinel compounds and many other oxides including Co2O3, Cr2O3, Fe2O3, MnO, MoO3, CoCr2O4, FeCr2O4, CoFe2O4, and CoMoO4 were observed in the passive films. The adsorbed and penetrated corrosive anion Cl-will be prone to breakdown the passive films with less Cr2O3, CoCr2O4 and MoO3 to form pitting corrosion (also include other localized corrosion, such as intergranular corrosion and crevice corrosion). The microstructure of the hcp martensite with the fcc matrix has played an important role in the propagation of the localized anodic dissolution in the form of cleavage and quasi-cleavage. The theoretical calculations are in good agreement with the experimental observations. This paper paves a way for the future devel-opment of high-performance Co-based entropic alloys served in some harsh environments.

  • 47.
    Wang, Wei
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Northeast Elect Power Univ, Dept Chem Engn, Jilin 132012, Jilin, Peoples R China..
    Wang, Yong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Process. Hanyang Univ, Dept Mat Sci & Chem Engn, Ansan 15588, South Korea..
    Mu, Wangzhong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures. Northeastern Univ, Sch Met, Key Lab Electromagnet Proc Mat, Minist Educ, Shenyang 110819, Peoples R China..
    Park, Joo Hyun
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Process. Hanyang Univ, Dept Mat Sci & Chem Engn, Ansan 15588, South Korea..
    Kong, Hui
    Anhui Univ Technol, Sch Met Engn, Maanshan 243002, Anhui, Peoples R China..
    Sukenaga, Sohei
    Tohoku Univ, Inst Multidisciplinary Res Adv Mat, Aoba Ku, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan..
    Shibata, Hiroyuki
    Tohoku Univ, Inst Multidisciplinary Res Adv Mat, Aoba Ku, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan..
    Larsson, Henrik
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures. Thermo Calc Software, Råsundav 18, SE-16767 Solna, Sweden..
    Mao, Huahai
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures. Thermo Calc Software, Råsundav 18, SE-16767 Solna, Sweden..
    Inclusion engineering in Co-based duplex entropic alloys2021In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 210, article id 110097Article in journal (Refereed)
    Abstract [en]

    Co-based duplex entropic alloy is designed very recently to replace pure Co as a major component of the binder phase for cemented carbide cutting tools. This work aims to provide a fundamental study of oxide inclusion characteristics in the duplex fcc + hcp Co-based entropic alloys. It is found that the Co85-xCrxFe7.5Ni7.5 (x = 15, 30 at.%) alloys hold the highest liquidus (T-liq) and solidus (T-sol) temperatures, compare with the Co85-xCrxMn7.5Ni7.5 (x = 15, 30 at.%) and Co77.5-xCrxFe7.5Mn7.5Ni7.5 (x = 15, 30 at.%) alloys. For each grade, the increasing Cr content leads to a decrease of T-sol and T-liq temperatures. It is also noted that there is an approximate 100 degrees C of undercooling exists in each grade during the solidification. The stable oxide inclusion in the Co85-xCrxMn7.5Ni7.5 and Co77.5-xCrxFe7.5Mn7.5Ni7.5 alloys is the MnCr2O4 type, while Cr2O3 is the main stable inclusion in the Co85-xCrxFe7.5Ni7.5 alloy. Furthermore, the size range of the MnCr2O4 particles is larger than that of Cr2O3. The theoretical calculation shows that MnCr2O4 has a higher coagulation coefficient than Cr2O3 does. This is due to the influence of the thermo-physical parameters, i.e. the interfacial energy between the oxide and the alloy and the viscosity of liquid alloy. The theoretical calculation fits well with the experimental findings.

  • 48.
    Wang, Xuying
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Hedberg, Jonas
    Surface Science Western, The University of Western Ontario, 999 Collip Circle, London, Ontario N6G 0J3, Canada.
    Nie, Heng-Yong
    Surface Science Western, The University of Western Ontario, 999 Collip Circle, London, Ontario N6G 0J3, Canada; Dept. of Physics and Astronomy, The University of Western Ontario, 1151 Richmond Str, London, Ontario N6A 5B7, Canada.
    Biesinger, Mark C.
    Surface Science Western, The University of Western Ontario, 999 Collip Circle, London, Ontario N6G 0J3, Canada; Dept. of Chemistry, The University of Western Ontario, 1151 Richmond Str, London, Ontario N6A 5B7, Canada.
    Odnevall, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. AIMES - Center for the Advancement of Integrated Medical and Engineering Sciences at Karolinska Institutet and KTH Royal Institute of Technology, Stockholm, Sweden; Department of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
    Hedberg, Yolanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. Surface Science Western, The University of Western Ontario, 999 Collip Circle, London, Ontario N6G 0J3, Canada; Dept. of Chemistry, The University of Western Ontario, 1151 Richmond Str, London, Ontario N6A 5B7, Canada.
    Location of cobalt impurities in the surface oxide of stainless steel 316L and metal release in synthetic biological fluids2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 215, p. 110524-, article id 110524Article in journal (Refereed)
    Abstract [en]

    Since 2021, cobalt (Co) is in Europe classified as carcinogen in quantities exceeding 0.1 wt-%. This affects nickel-rich stainless steels, which contain about 0.2 wt-% Co impurities. Previous findings show the bioaccessibility of Co in stainless steel to be primarily determined by the corrosion resistance. It has been unclear whether Co is distributed heterogeneously in the alloy and the outermost surface and whether a specific location would pose a risk for Co release under specific exposure conditions. This study aimed at locating Co in stainless steel 316L (0.2 wt-% Co) surfaces prior to and after exposure to different synthetic body fluids for 24 h at 37 °C. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICPMS) investigated the location of Co in the surface oxide and extent of release along with other metals (iron, chromium, nickel, and manganese) into synthetic biological fluids (gastric fluid, pH 1.5; lysosomal fluid, pH 4.5; phosphate buffered saline-PBS, pH 7.4). Co was homogeneously distributed along with metallic nickel beneath the surface oxide and co-released with other metals upon surface reformation and passivation. Exposure in PBS resulted in the incorporation of both Co and phosphate in the oxide. 

  • 49.
    Wang, Xuying
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science.
    Noël, J. J.
    Odnevall Wallinder, Inger
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. AIMES; Department of Neuroscience, Karolinska Institutet.
    Hedberg, Yolanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. The University of Western Ontario.
    Metal bioaccessibility in synthetic body fluids – A way to consider positive and negative alloying effects in hazard assessments2021In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 198, article id 109393Article in journal (Refereed)
    Abstract [en]

    Hazard classification of metal alloys is today generally based on their bulk content, an approach that seldom reflects the extent of metal release for a given environment. Such information can instead be achieved via bioelution testing under simulated physiological conditions. The use of bioelution data instead of bulk contents would hence refine the current hazard classification of alloys and enable grouping. Bioelution data have been generated for nickel (Ni) and cobalt (Co) released from several stainless steel grades, one low-alloyed steel, and Ni and Co metals in synthetic sweat, saliva and gastric fluid, for exposure periods from 2 to 168 h. All stainless steel grades with bulk contents of 0.11–10 wt% Ni and 0.019–0.24 wt% Co released lower amounts of Ni (up to 400-fold) and Co (up to 300-fold) than did the low-alloyed steel (bulk content: 0.034% Ni, 0.015% Co). They further showed a relative bioaccessibility of Ni and Co considerably less than 1, while the opposite was the case for the low-alloyed steel. Surface oxide- and electrochemical corrosion investigations explained these findings in terms of the high passivity of the stainless steels related to the Cr(III)-rich surface oxide that readily adapted to the fluid acidity and chemistry.

  • 50.
    Xuan, Changji
    et al.
    Sandvik Mfg Solut AB, Addit Mfg Div, SE-81181 Sandviken, Sweden..
    Mu, Wangzhong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures.
    New insights of heterogeneous nucleation and anisotropic growth of acicular ferrite on non-metallic inclusion2022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 221, article id 110892Article in journal (Refereed)
    Abstract [en]

    This work studies the acicular ferrite (AF) nucleation and growth from a classical defect, i.e. non-metallic inclusion surface. The heterogeneous AF-nucleation probability on NMI is predicted by a mathematical model following the classical nucleation theory. The calculation results are in consistent with the exper-imental data. The current model includes the exact form of the activation energy and Zeldovich factor for heterogeneous nucleation on pre-existing spherical surface. It generates an interaction map that for the first time quantitatively describes the superposition influences of the interfacial energies and NMI-size on the AF-nucleation potency. In the AF-growth aspect, we systematically reveal the single AF-plate evo-lution behavior through the synergy between the experimental observations and multiphase-field simu-lations. It is found that the AF-tip morphology is impacted by the misorientation angle between the favorable growth direction and normal vector. It also influences the AF-lengthening and widening kinet-ics. Additionally, the anisotropic stress field induced by the AF-NMI interface plays a significant role in controlling the complex curvature of the AF-plate. The current study opens new perspectives for under-standing the AF-precipitation mechanisms.

12 1 - 50 of 63
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf