Ändra sökning
Avgränsa sökresultatet
1 - 45 av 45
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1. Amin Yavari, S.
    et al.
    Croes, M.
    Akhavan, B.
    Jahanmard, F.
    Eigenhuis, C. C.
    Dadbakhsh, S.
    KTH, Skolan för industriell teknik och management (ITM).
    Vogely, H. C.
    Bilek, M. M.
    Fluit, A. C.
    Boel, C. H. E.
    van der Wal, B. C. H.
    Vermonden, T.
    Weinans, H.
    Zadpoor, A. A.
    Layer by layer coating for bio-functionalization of additively manufactured meta-biomaterials2020Ingår i: Additive Manufacturing, ISSN 2214-8604, Vol. 32Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Additive manufacturing has facilitated fabrication of complex and patient-specific metallic meta-biomaterials that offer an unprecedented collection of mechanical, mass transport, and biological properties as well as a fully interconnected porous structure. However, applying meta-biomaterials for addressing unmet clinical needs in orthopedic surgery requires additional surface functionalities that should be induced through tailor-made coatings. Here, we developed multi-functional layer-by-layer coatings to simultaneously prevent implant-associated infections and stimulate bone tissue regeneration. We applied multiple layers of gelatin- and chitosan-based coatings containing either bone morphogenetic protein (BMP)-2 or vancomycin on the surface of selective laser melted porous structures made from commercial pure Titanium (CP Ti) and designed using a triply periodic minimal surface (i.e., sheet gyroid). The additive manufacturing process resulted in a porous structure and met the the design values comparatively. X-ray photoelectron spectroscopy spectra confirmed the presence and composition of the coating layers. The release profiles showed a continued release of both vancomycin and BMP-2 for 2–3 weeks. Furthermore, the developed meta-biomaterials exhibited a very strong antibacterial behavior with up to 8 orders of magnitude reduction in both planktonic and implant-adherent bacteria and no signs of biofilm formation. The osteogenic differentiation of mesenchymal stem cells was enhanced, as shown by two-fold increase in the alkaline phosphatase activity and up to four-fold increase in the mineralization of all experimental groups containing BMP-2. Eight-week subcutaneous implantation in vivo showed no signs of a foreign body response, while connective tissue ingrowth was promoted by the layer-by-layer coating. These results unequivocally confirm the superior multi-functional performance of the developed biomaterials.

  • 2. Dadbakhsh, S.
    et al.
    Hao, L.
    Effect of Al alloys on selective laser melting behaviour and microstructure of in situ formed particle reinforced composites2012Ingår i: Journal of Alloys and Compounds, Vol. 541, nr 0, s. 328-334Artikel i tidskrift (Refereegranskat)
  • 3. Dadbakhsh, S.
    et al.
    Hao, L.
    Effect of Fe2O3 content on microstructure of Al powder consolidated parts via selective laser melting using various laser powers and speeds2014Ingår i: International Journal of Advanced Manufacturing Technology, Vol. 73, nr 9-12, s. 1453-1463Artikel i tidskrift (Refereegranskat)
  • 4. Dadbakhsh, S.
    et al.
    Hao, L.
    Effect of hot isostatic pressing (HIP) on Al composite parts made from laser consolidated Al/Fe2O3 powder mixtures2012Ingår i: Journal of Materials Processing Technology, Vol. 212, nr 11, s. 2474-2483Artikel i tidskrift (Refereegranskat)
  • 5. Dadbakhsh, S.
    et al.
    Hao, L.
    In situ formation of particle reinforced Al matrix composite by selective laser melting of Al/Fe 2O 3 powder mixture2012Ingår i: Advanced Engineering Materials, Vol. 14, nr 1-2, s. 45-48Artikel i tidskrift (Refereegranskat)
  • 6. Dadbakhsh, S.
    et al.
    Hao, L.
    Jerrard, P. G. E.
    Zhang, D. Z.
    Experimental investigation on selective laser melting behaviour and processing windows of in situ reacted Al/Fe2O3 powder mixture2012Ingår i: Powder Technology, Vol. 231, nr 0, s. 112-121Artikel i tidskrift (Refereegranskat)
  • 7. Dadbakhsh, S.
    et al.
    Hao, L.
    Kong, C. Y.
    Surface finish improvement of LMD samples using laser polishing2010Ingår i: Virtual and Physical Prototyping, Vol. 5, nr 4, s. 215-221Artikel i tidskrift (Refereegranskat)
  • 8. Dadbakhsh, S.
    et al.
    Hao, L.
    Kruth, J.-P.
    Selective laser melting towards manufacture of three dimensional in situ Al matrix composites: A review2013Ingår i: High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping - Proceedings of the 6th International Conference on Advanced Research and Rapid Prototyping, VR@P, 2013Konferensbidrag (Refereegranskat)
  • 9. Dadbakhsh, S.
    et al.
    Hao, L.
    Sewell, N.
    Effect of selective laser melting layout on the quality of stainless steel parts2012Ingår i: Rapid Prototyping Journal, Vol. 18, nr 3, s. 241-249Artikel i tidskrift (Refereegranskat)
  • 10. Dadbakhsh, S.
    et al.
    Hao, L.
    Sewell, N.
    Jerrard, P.
    Direct fabrication of an in-situ Al composite using selective laser melting process2009Ingår i: Innovative developments in design and manufacturing advanced research in virtual and rapid prototyping: proceedings of the 4th International Conference on Advanced Research in Virtual and Rapid Prototyping, Leiria: CRC Press , 2009Konferensbidrag (Refereegranskat)
  • 11. Dadbakhsh, S.
    et al.
    Karimi Taheri, A.
    Smith, C. W.
    Strengthening study on 6082 Al alloy after combination of aging treatment and ECAP process2010Ingår i: Materials Science and Engineering A, Vol. 527, nr 18-19, s. 4758-4766Artikel i tidskrift (Refereegranskat)
  • 12. Dadbakhsh, S.
    et al.
    Taheri, A. K.
    Study on static strain aging of 6082 aluminium alloy2010Ingår i: Materials Science and Technology, Vol. 26, nr 2, s. 169-175Artikel i tidskrift (Refereegranskat)
  • 13. Dadbakhsh, S.
    et al.
    Vrancken, B.
    Kruth, J. P.
    Luyten, J.
    Van Humbeeck, J.
    Texture and anisotropy in selective laser melting of NiTi alloy2016Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 650, s. 225-232Artikel i tidskrift (Refereegranskat)
  • 14. Dadbakhsh, Sasan
    et al.
    Hao, Liang
    Effect of Layer Thickness in Selective Laser Melting on Microstructure of Al/5wt.%Fe2O3 Powder Consolidated Parts2014Ingår i: The Scientific World Journal, Vol. 2014, s. 10-Artikel i tidskrift (Refereegranskat)
  • 15.
    Dadbakhsh, Sasan
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion. Katholieke Univ Leuven, PMA, Dept Mech Engn, B-3001 Leuven, Belgium ; Flanders Make, B-3001 Leuven, Belgium.
    Mertens, Raya
    Katholieke Univ Leuven, PMA, Dept Mech Engn, B-3001 Leuven, Belgium.;Flanders Make, B-3001 Leuven, Belgium..
    Hao, Liang
    China Univ Geosci, Gemol Inst, Wuhan 430074, Hubei, Peoples R China..
    Van Humbeeck, Jan
    Katholieke Univ Leuven, Dept Mat Engn, B-3001 Leuven, Belgium..
    Kruth, Jean-Pierre
    Katholieke Univ Leuven, PMA, Dept Mech Engn, B-3001 Leuven, Belgium.;Flanders Make, B-3001 Leuven, Belgium..
    Selective Laser Melting to Manufacture "In Situ" Metal Matrix Composites: A Review2019Ingår i: Advanced Engineering Materials, ISSN 1438-1656, Vol. 21, nr 3, artikel-id 1801244Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    After a brief introduction on selective laser melting (SLM) and ex situ manufacture of metal matrix composites (MMCs), this paper reviews the capacities and benefits of SLM to activate and control various in situ reactions during fabrication of 3D parts. It introduces several systems (such as Al/Fe2O3, AlSi10Mg/SiC, Al/ZnO, Ti/C, Ti/SiC, Ti/Si3N4, Ti/Mo2C, Fe/SiC, etc.) used to manufacture Al-based, Ti-based, and steel-based in situ MMCs. Then, it illustrates the novel microstructural characteristics of these SLM-made in situ MMCs for different cases, as they may appear from nano-particles to nano-whiskers and dendritic reinforcements homogeneously distributed in a metal matrix. It also focuses on SLM associated in situ mechanisms, explaining how an in situ reaction propagates based on decomposition, diffusion, and reformation and how the growth mechanisms turn into different morphologies such as rounded particles, whiskers, or polygonal block shapes. The influence of various SLM parameters (such as energy density, laser power/speed, powder layer thickness, and the size of initial powder particles) and the SLM in situ challenges are also discussed.

  • 16. Dadbakhsh, Sasan
    et al.
    Mertens, Raya
    Vanmeensel, Kim
    Vleugels, Jef
    Humbeeck, Jan Van
    Kruth, Jean-Pierre
    In situ alloying and reinforcing of Al6061 during selective laser melting2018Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 74, s. 39-43Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work investigates the feasibility of a novel method to simultaneously alloy and reinforce a low alloyed Al alloy (i.e., Al6061) during selective laser melting (SLM) via in situ decomposition of zinc oxide (ZnO). Based on Gibbs free energy calculations, an Al6061+6wt%ZnO powder mixture is designed and prepared. The thermal decomposition of ZnO, resulting in the formation of Al oxide and free Zn, simultaneously alloys and reinforces the Al matrix. This also provides extra thermal energy that alters the dynamics of the melt pool and necessitates a completely different set of optimised SLM parameters compared to traditional Al alloys. After SLM, it is shown that this method can successfully reinforce the Al matrix with numerous nanometer sized oxide particles (typically ~ 50-120 nm). Despite this clear success to manufacture in situ reinforced Al composites by SLM, the applied method could not avoid partial Zn evaporation (limiting in situ alloying) and could not successfully suppress the cracking that also occurs after SLM of unreinforced Al6061.

  • 17. Dadbakhsh, Sasan
    et al.
    Speirs, Mathew
    Kruth, Jean-Pierre
    Schrooten, Jan
    Luyten, Jan
    Van Humbeeck, Jan
    Effect of SLM Parameters on Transformation Temperatures of Shape Memory Nickel Titanium Parts2014Ingår i: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648, Vol. 16, nr 9, s. 1140-1146Artikel i tidskrift (Refereegranskat)
  • 18. Dadbakhsh, Sasan
    et al.
    Speirs, Mathew
    Kruth, Jean-Pierre
    Van Humbeeck, Jan
    Influence of SLM on shape memory and compression behaviour of NiTi scaffolds2015Ingår i: CIRP annals, ISSN 0007-8506, E-ISSN 1726-0604, Vol. 64, nr 1, s. 209-212Artikel i tidskrift (Refereegranskat)
  • 19. Dadbakhsh, Sasan
    et al.
    Speirs, Mathew
    Van Humbeeck, Jan
    Kruth, Jean-Pierre
    Laser additive manufacturing of bulk and porous shape-memory NiTi alloys: From processes to potential biomedical applications2016Ingår i: MRS bulletin, ISSN 0883-7694, E-ISSN 1938-1425, Vol. 41, nr 10, s. 765-774Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    NiTi alloys are well known not only due to their exceptional shape-memory ability to recover their primary shape, but also because they show high ductility, excellent corrosion and wear resistance, and good biological compatibility. They have received significant attention especially in the field of laser additive manufacturing (AM). Among laser AM techniques, selective laser melting and laser metal deposition are utilized to exploit the unique properties of NiTi for fabricating complex shapes. This article reviews the properties of bulk and porous laser-made NiTi alloys as influenced by both process and material parameters. The effects of processing parameters on density, shape-memory response, microstructure, mechanical properties, surface corrosion, and biological properties are discussed. The article also describes potential opportunities where laser AM processes can be applied to fabricate dedicated NiTi components for medical applications.

  • 20. Dadbakhsh, Sasan
    et al.
    Speirs, Mathew
    Yablokova, Ganna
    Kruth, Jean-Pierre
    Schrooten, Jan
    Luyten, Jan
    Van Humbeeck, Jan
    The Minerals, Metals
    Materials, Society
    Microstructural Analysis and Mechanical Evaluation of Ti-45Nb Produced by Selective Laser Melting towards Biomedical Applications2015Ingår i: TMS2015 Supplemental Proceedings, John Wiley & Sons, Inc. , 2015Konferensbidrag (Refereegranskat)
  • 21. Dadbakhsh, Sasan
    et al.
    Verbelen, Leander
    Vandeputte, Tom
    Strobbe, Dieter
    Van Puyvelde, Peter
    Kruth, Jean-Pierre
    Effect of Powder Size and Shape on the SLS Processability and Mechanical Properties of a TPU Elastomer2016Ingår i: Physics Procedia, ISSN 1875-3892, E-ISSN 1875-3892, Vol. 83, s. 971-980Artikel i tidskrift (Refereegranskat)
  • 22. Gorgin Karaji, Z.
    et al.
    Speirs, M.
    Dadbakhsh, S.
    Kruth, J. P.
    Weinans, H.
    Zadpoor, A. A.
    Amin Yavari, S.
    Additively Manufactured and Surface Biofunctionalized Porous Nitinol2016Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252Artikel i tidskrift (Refereegranskat)
  • 23. Hao, L.
    et al.
    Dadbakhsh, S.
    Materials and process aspects of selective laser melting of metals and metal matrix composites: A review2009Ingår i: Zhongguo Jiguang/Chinese Journal of Lasers, ISSN 0258-7025, Vol. 36, nr 12, s. 3192-3203Artikel i tidskrift (Refereegranskat)
  • 24. Hao, L.
    et al.
    Dadbakhsh, S.
    Seaman, O.
    Felstead, M.
    Selective laser melting of a stainless steel and hydroxyapatite composite for load-bearing implant development2009Ingår i: Journal of Materials Processing Technology, Vol. 209, nr 17, s. 5793-5801Artikel i tidskrift (Refereegranskat)
  • 25. Hao, L.
    et al.
    Raymond, D.
    Strano, G.
    Dadbakhsh, S.
    Enhancing the sustainability of additive manufacturing2010Ingår i: IET Conference Publications, 2010Konferensbidrag (Refereegranskat)
  • 26. Jadhav, S. D.
    et al.
    Dadbakhsh, S.
    Goossens, L.
    Kruth, J. P.
    Van Humbeeck, J.
    Vanmeensel, K.
    Influence of selective laser melting process parameters on texture evolution in pure copper2019Ingår i: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 270, s. 47-58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work, Crack-Free pure copper parts with relative densities exceeding 98% are processed by selective laser melting (SLM) using a high-power fiber laser. The influence of different laser scan parameters such as hatch spacing, laser power and scan speed on the texture evolution in the manufactured parts is determined. On the top surfaces, a clear interrelationship between laser scan parameters and crystallographic texture is established. This shows that the texture at the top surface can be very strong especially when a high laser power and a low scanning speed is used. However, a random texture exists in the core of the sample due to successive re-melting and altered heat gradients induced by the application of a 90° scan rotation between subsequent layers. A maximum electrical conductivity of 88% of the International Annealed Copper Standard (IACS) is achieved in the as-built state. Damage to the optical mirror of the SLM machine is observed and recommendations for sustainable up-scalability are proposed.

  • 27. Jadhav, Suraj Dinkar
    et al.
    Dadbakhsh, Sasan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Chen, Rong
    Shabadi, Rajashekhara
    Kruth, Jean-Pierre
    Van Humbeeck, Jan
    Vanmeensel, Kim
    Modification of Electrical and Mechanical Properties of Selective Laser-Melted CuCr0.3 Alloy Using Carbon Nanoparticles2019Ingår i: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648, Vol. n/a, nr n/a, artikel-id 1900946Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein, the influence of carbon nanoparticle addition on the selective laser melting (SLM) behavior and the resultant properties of gas-atomized CuCr0.3 powder are investigated. The carbon addition neither affects the powder flowability, nor its packing density, but it significantly enhances the optical absorption for infrared radiation. Despite the improved optical absorption of the powder bed after carbon addition, a comparable SLM behavior is observed for both virgin and carbon-mixed CuCr0.3 powders. Furthermore, the addition of carbon nanoparticles facilitates in situ deoxidation of copper and chromium oxides present in the CuCr0.3 powder. Accordingly, a larger fraction of chromium is obtained in its metallic form in the as-built carbon-mixed CuCr0.3 part. The presence of metallic chromium allows tailoring of the mechanical and electrical properties by postheat treatments (HTs). The best combination of mechanical (tensile strength of 298?±?19?MPa, yield strength of 208?±?18?MPa, ductility of 21?±?4%) and electrical (87?±?1% international annealed copper standards [% IACS]) properties is realized for the carbon-mixed CuCr0.3 alloy after a direct age hardening HT. The improvement in mechanical properties is attributed to the precipitation of nanometer-sized, coherent, and metallic chromium precipitates in the copper matrix.

  • 28. Jadhav, Suraj Dinkar
    et al.
    Dadbakhsh, Sasan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion. PMA, Department of Mechanical Engineering, Belgium.
    Vleugels, Jozef
    Hofkens, Johan
    Puyvelde, Peter Van
    Yang, Shoufeng
    Kruth, Jean-Pierre
    Humbeeck, Jan Van
    Vanmeensel, Kim
    Influence of Carbon Nanoparticle Addition (and Impurities) on Selective Laser Melting of Pure Copper2019Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, nr 15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The addition of 0.1 wt % carbon nanoparticles significantly improved the optical absorption and flowability of gas-atomized copper powder. This facilitated selective laser melting (SLM) by reducing the required laser energy density to obtain 98% dense parts. Moreover, the carbon addition led to an in situ de-oxidation of the copper parts during the SLM process. The properties of the as-built copper parts were limited to a tensile strength of 125 MPa, a ductility of 3%, and an electrical conductivity of 22.7 × 106 S/m, despite the advantageous effect of carbon on the powder characteristics and SLM behavior. The modest mechanical properties were associated with the segregation of carbon nanoparticles and other impurities, such as phosphorus and oxygen along grain boundaries of epitaxially grown grains. Whereas, the low electrical conductivity was mainly attributed to the phosphorus impurity in solid-solution with copper.

  • 29. Jadhav, Suraj Dinkar
    et al.
    Van Cauwenbergh, Pierre
    Lietaert, Karel
    Van Humbeeck, Jan
    Kruth, Jean-Pierre
    Dadbakhsh, Sasan
    Ivekovic, Aljaz
    Vanmeensel, Kim
    SLM of CuNi10 alloy using gas atomized powder2017Ingår i: Materials Science and Technology, Pittsburgh, Pennsylvania, USA, 2017Konferensbidrag (Refereegranskat)
  • 30. Jean-Pierre, Kruth
    et al.
    Sasan, Dadbakhsh
    Bey, Vrancken
    Karolien, Kempen
    Jef, Vleugels
    Jan Van, Humbeeck
    Additive Manufacturing of Metals via Selective Laser Melting: Process Aspects and Material Developments2015Ingår i: Additive Manufacturing, CRC Press, 2015Kapitel i bok, del av antologi (Refereegranskat)
  • 31. Jerrard, P. G. E.
    et al.
    Hao, L.
    Dadbakhsh, S.
    Evans, K. E.
    Consolidation behaviour and microstructural characteristics of Al and a mixture of Al-Cu alloy powders following selective laser melting processing2011Ingår i: Lasers in engineering (Print), ISSN 0898-1507, E-ISSN 1029-029X, Vol. 22, nr 5-6, s. 371-381Artikel i tidskrift (Refereegranskat)
  • 32. Mertens, R.
    et al.
    Dadbakhsh, S.
    Humbeeck, J. Van
    Kruth, J.-P.
    Application of base plate preheating during selective laser melting2018Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 74, s. 5-11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Base plate preheating is one of the recent enhancing tools added to the process of Selective Laser Melting (SLM). This tool aims at a reduction of thermal stresses in SLM parts, achieved by decreasing the thermal gradients during SLM processing. In the current study, base plate preheating up to a temperature of 400°C is applied during SLM of 4 different materials, including aluminum 7075 alloy, nickel alloy Hastelloy X, H13 tool steel and CoCr. General trends, as well as material specific effects are discussed regarding part density, crack formation, internal stresses, microstructure and mechanical properties. These show how base plate preheating can induce different influences according to each particular material category.

  • 33. 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 sintering2016Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 109, s. 520-529Artikel i tidskrift (Refereegranskat)
    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.

  • 34. Speirs, Mathew
    et al.
    Dadbakhsh, Sasan
    KU Leuven, Belgium.
    Buls, S
    Kruth, JP
    Van Humbeeck, J
    Schrooten, J
    Luyten, Jan
    The effect of SLM parameters on geometrical characteristics of open porous NiTi scaffolds2013Ingår i: High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping - Proceedings of the 6th International Conference on Advanced Research and Rapid Prototyping, VR@P 2013, Leiria, Portugal: CRC Press , 2013, s. 309-314Konferensbidrag (Refereegranskat)
    Abstract [en]

    Selective Laser Melting (SLM) is a promising technique for the production of biometallic scaffolds for orthopaedic applications. To produce successful scaffolds, the laser parameters should be carefully selected in order to achieve open porosity especially when pores are <1000 μm. In this study, we investigate the effect of different laser parameters (capable to produce dense bulk NiTi samples) on production of scaffolds with open porosities of 1000 μm and varying strut thicknesses 100-300 μm. Two different sets of laser parameters were used: 40W laser power with 160 mm/s scanning velocity and 250W with 1000 mm/s, corresponding to low and high laser parameters respectively. Micro-CT scanning experiments were carried out to illustrate the limitations of laser parameters in production of open porous scaffolds. Volume fraction and closed porosity were assessed. It was found that a large CAD mismatch was observed in the building (XZ) direction and internal porosity appears within struts of the samples produced with high laser processing parameters. The residual particles on struts were also shown to increase as strut thickness increases.

  • 35. Speirs, Mathew
    et al.
    Wang, X.
    Van Baelen, S.
    Ahadi, A.
    Dadbakhsh, Sasan
    Department of Mechanical Engineering, KU Leuven, Louvain, Belgium.
    Kruth, J. -P
    Van Humbeeck, J.
    On the Transformation Behavior of NiTi Shape-Memory Alloy Produced by SLM2016Ingår i: Shape Memory and Superelasticity, ISSN 2199-3858, Vol. 2, nr 4, s. 310-316Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Selective laser melting has been applied as a production technique of nickel titanium (NiTi) parts. In this study, the scanning parameters and atmosphere control used during production were varied to assess the effects on the final component transformation criteria. Two production runs were completed: one in a high (~1800 ppm O2) and one in a low-oxygen (~220 ppm O2) environment. Further solution treatment was applied to analyze precipitation effects. It was found that the transformation temperature varies greatly even at identical energy densities highlighting the need for further in-depth investigations. In this respect, it was observed that oxidation was the dominating factor, increased with higher laser power adapted to higher scanning velocity. Once the atmospheric oxygen content was lowered from 1800 to about 220 ppm, a much smaller variation of transformation temperatures was obtained. In addition to oxidation, other contributing factors, such as nickel depletion (via evaporation during processing) as well as thermal stresses and textures, are further discussed and/or postulated. These results demonstrated the importance of processing and material conditions such as O2 content, powder composition, and laser scanning parameters. These parameters should be precisely controlled to reach desired transformation criteria for functional components made by SLM.

  • 36. Strobbe, Dieter
    et al.
    Dadbakhsh, Sasan
    Department of Mechanical Engineering, KU Leuven, Division Production Engineering, Machine Design and Automation, Heverlee, Belgium.
    Verbelen, Leander
    Van Puyvelde, Peter
    Kruth, Jean-Pierre
    Selective laser sintering of polystyrene: a single-layer approach2018Ingår i: Plastics, rubber and composites, ISSN 1465-8011, E-ISSN 1743-2898, Vol. 47, nr 1, s. 2-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Selective laser sintering (SLS) is a powder bed-based additive manufacturing technique to produce complex three-dimensional parts. Although every thermoplastic polymer theoretically can be processed via this technique, variable material behaviour complicates the optimisation of the processing parameters. This study investigates the processability of polystyrene by SLS by evaluating bed temperatures and laser parameters. The morphology of single-layer parts is examined through scanning electron microscopy and roughness measurements to find an indication for the optimal processing parameters. Additionally, the effect of carbon black (CB) (as a colouring additive) on the processability of polystyrene is studied. It is found that polystyrene without CB is processable at a bed temperature just below the glass transition temperature. The addition of CB reduces the consolidation of single layers. The single-layer investigation is extended to, and shown to correlate with, a preliminary investigation of the relative density of multilayer parts.

  • 37.
    Tang, Danna
    et al.
    China Univ Geosci, Gemol Inst, Wuhan 430074, Hubei, Peoples R China.;Hubei Jewelry Engn Technol Res Ctr, Wuhan 430074, Hubei, Peoples R China..
    Hao, Liang
    China Univ Geosci, Gemol Inst, Wuhan 430074, Hubei, Peoples R China.;Hubei Jewelry Engn Technol Res Ctr, Wuhan 430074, Hubei, Peoples R China..
    Li, Yan
    China Univ Geosci, Gemol Inst, Wuhan 430074, Hubei, Peoples R China.;Hubei Jewelry Engn Technol Res Ctr, Wuhan 430074, Hubei, Peoples R China..
    Li, Zheng
    China Univ Geosci, Gemol Inst, Wuhan 430074, Hubei, Peoples R China.;Hubei Jewelry Engn Technol Res Ctr, Wuhan 430074, Hubei, Peoples R China..
    Dadbakhsh, Sasan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Dual gradient direct ink writing for formation of kaolinite ceramic functionally graded materials2020Ingår i: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 814, artikel-id UNSP 152275Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Direct ink writing (DIW) technique has emerged as a powerful tool to create specific functionally graded materials (FGMs) products with macroscopic and microscopic porous architectures and mechanical properties. In order to explore the DIW process control method of ceramic composite FGMs, several additives (e.g., polysorbate, liquid paraffin and water) were mixed with kaolinite and barite powders to print the gradient materials with difference in both material compositions and structures. A stable ceramic slurry with a viscosity of 2.66-3.66 GP s at 5 MPa atmospheric pressure has been formulated by uniformly mixing 2 mm and 10 mm particles. Besides, the optimized flow rate of 150 mml/s and thickness of 0.5 mm were well proved to obtain good stacking of the slurry, whereas, the change of velocity shows little effect on the forming quality. The meso/macro pores of the gradient component can be achieved by adjusting the printing and sintering processes. The dual-extrusion DIW method presented here is versatile to be adapted to a wide range of biomimetic ceramic materials for the fabrication of FGMs objects with unprecedented properties.

  • 38. Vanmeensel, Kim
    et al.
    Lietaert, Karel
    Vrancken, Bey
    Dadbakhsh, Sasan
    KU Leuven, Leuven, Belgium.
    Li, Xiaopeng
    Kruth, Jean-Pierre
    Krakhmalev, Pavel
    Yadroitsev, Igor
    Van Humbeeck, Jan
    8 - Additively manufactured metals for medical applications2018Ingår i: Additive Manufacturing: Materials, Processes, Quantifications and Applications, Butterworth-Heinemann , 2018, s. 261-309Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Additive Manufacturing (AM) allows to produce improved, custom made, patient specific and complex shaped medical implants. Both mechanical and biological aspects as well as type of implant and patient specific requirements determine the shape of the implant and the material it will be made of. The current chapter reviews the metals and metallic alloys that can be successfully processed by powder bed fusion AM technologies, focusing on the interrelationship between their chemistry and microstructure, on one hand, and their biological and mechanical behavior, respectively, on the other hand.

  • 39. Verbelen, Leander
    et al.
    Dadbakhsh, Sasan
    Kruth, Jean-Pierre
    Van Puyvelde, Peter
    Characterization of different PA powders to determine their applicability for laser sintering2015Konferensbidrag (Refereegranskat)
  • 40. Verbelen, Leander
    et al.
    Dadbakhsh, Sasan
    bKU Leuven, University of Leuven, Department of Mechanical Engineering, Leuven, Belgium.
    Van den Eynde, Michael
    Kruth, Jean-Pierre
    Goderis, Bart
    Van Puyvelde, Peter
    Characterization of polyamide powders for determination of laser sintering process ability2016Ingår i: European Polymer Journal, ISSN 0014-3057, E-ISSN 1873-1945, Vol. 75, s. 163-174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the increasing use of laser sintering for the production of end-use parts, there is considerable interest in developing new and improved polymer materials for this technique. Due to the complexity of the process, however, materials are subject to very specific requirements in order to be easy processable. To gain a better understanding of these material requirements, this study investigates the currently most widely used material family: polyamides. Four commercial polyamide sintering grades, including two polyamide-12 grades, one polyamide-11 and one polyamide-6 grade, are characterized, using a new screening approach that encompasses all material properties essential for laser sintering. These include powder characteristics, melt flow, and solidification behavior of the polymer. The study reveals several particular characteristics of polyamides that explain the current popularity of this material family for laser sintering, and may be used as a guideline for finding new materials for the process.

  • 41. Verbelen, Leander
    et al.
    Dadbakhsh, Sasan
    KU Leuven—University of Leuven, Department of Mechanical Engineering, Leuven, Belgium.
    Van den Eynde, Michael
    Strobbe, Dieter
    Kruth, Jean-Pierre
    Goderis, Bart
    Van Puyvelde, Peter
    Analysis of the material properties involved in laser sintering of thermoplastic polyurethane2017Ingår i: Additive Manufacturing, ISSN 2214-8604, Vol. 15, s. 12-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As laser sintering is increasingly being used for the production of actual end-use parts, there is considerable interest in developing materials that would enable new applications for this technique. Considering their properties and current applications, elastomeric polymers such as thermoplastic polyurethanes (TPU) have a very high potential in this regard. This study investigates the material properties that are involved in TPU sintering through the analysis of four distinct TPU grades. Examined parameters include powder flow, rheology of the melt and shrinkage and hardening behavior. It is found that, even though the particle morphology is not optimum, smooth and dense powder layers can be deposited for the investigated powders. Low melt viscosity and low shrinkage upon hardening further enable these materials to be easily processed into functional parts. Remaining issues, however, are part porosity and material degradation. The findings in this study provide clear links between material properties and behavior during laser sintering, and result in guidelines for future selection of TPU grades.

  • 42. Vrancken, Bey
    et al.
    Dadbakhsh, Sasan
    KTH, Skolan för industriell teknik och management (ITM).
    Mertens, Raya
    Vanmeensel, Kim
    Vleugels, Jef
    Yang, Shoufeng
    Kruth, Jean-Pierre
    Selective Laser Melting process optimization of Ti–Mo–TiC metal matrix composites2019Ingår i: CIRP annals, ISSN 0007-8506, E-ISSN 1726-0604, Vol. 68, s. 221-224Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Selective Laser Melting (SLM) was used to process a powder mixture of CP Ti, 6.5 wt% Mo and 3.5 wt% Mo2C. The process parameters were optimized to obtain full-density, crack free parts. After the in situ decomposition of Mo2C in favor of the formation of TiC, the material consisted of a homogeneous dispersion of submicrometer sized TiC platelets in a β-(Ti,Mo) matrix exhibiting a high hardness up to 550 HV and compressive yield stress of 1164 ± 37 MPa. The microstructure and mechanical properties could be tailored by variation of the process parameters within the high-density processing window, as well as through post-process heat treatments.

  • 43. Yablokova, Ganna
    et al.
    Dadbakhsh, Sasan
    PMA, Department of Mechanical Engineering, K U Leuven; Celestijnenlaan 300; Leuven 3001, Belgium.
    Speirs, Mathew
    Khangholi, Aliakbar
    Kruth, Jean-Pierre
    Luyten, Jan
    Schrooten, Jan
    Van Humbeeck, Jan
    Surface Treatment of Ti-45Nb Open Porous Structures towards Biomedical Applications: A Modified Approach2015Ingår i: TMS2015 Supplemental Proceedings, John Wiley & Sons, 2015, s. 515-520Konferensbidrag (Refereegranskat)
  • 44.
    Zhao, Xiaoyu
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Rashid, Amir
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi. KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Produktionssystem.
    Dadbakhsh, Sasan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Influence of Contouring and depth of machining on tensile properties of Inconel 625 made by Electron Beam Melting2019Ingår i: Metal Additive Manufacturing Conference: Laser Melting, Electon Beam Melting & Direct Energy Deposition Processes, 2019, s. 118-127Konferensbidrag (Refereegranskat)
    Abstract [en]

    This research is to evaluate the manufacturability and to characterize the performance of Inconel 625 (IN625) by electron beam melting (EBM). After further modifying the commercial EBM parameters for Inconel 718, such as speed function for hatching and the line offset for both hatching and multi-beam contouring, nearly full dense samples (over 99.7% of the wrought material) are produced. It is shown that no contouring strategy generates a relatively rougher surface (approximately 29% in average) compared to the samples printed with contour, requiring even a further post-process machining. Furthermore, the microhardness after EBM is comparable to as-rolled and annealed IN625 material. The samples machined from bulk specimens exhibit good tensile properties regardless of the contouring strategy due to the high depth of machining (5.5mm). However, for the near-net shaped specimens with only 2.1 mm machining of the surfaces, elongation is significantly affected by the contouring strategy. This is in such a manner that the contoured near-net shape parts show relatively 32% less elongation compared to the samples without any contour. Accordingly, multi-beam contouring is better to be avoided to reach tensile properties comparable to the wrought material after a shallow machining, despite the fact that it can lead to a relative smoother surface finish after EBM.

  • 45.
    Zhao, Xiaoyu
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Rashid, Amir
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
    Dadbakhsh, Sasan
    KTH, Skolan för industriell teknik och management (ITM), Industriell produktion.
    Influence of Contouring and depth of machining on tensile properties of Inconel 625 made by Electron Beam Melting2019Ingår i: Metal Additive Manufacturing Conference: Laser Melting, Electon Beam Melting & Direct Energy Deposition Processes, 2019, s. 118-127Konferensbidrag (Refereegranskat)
    Abstract [en]

    This research is to evaluate the manufacturability and to characterize the performance of Inconel 625 (IN625) by electron beam melting (EBM). After further modifying the commercial EBM parameters for Inconel 718, such as speed function for hatching and the line offset for both hatching and multi-beam contouring, nearly full dense samples (over 99.7% of the wrought material) are produced. It is shown that no contouring strategy generates a relatively rougher surface (approximately 29% in average) compared to the samples printed with contour, requiring even a further post-process machining. Furthermore, the microhardness after EBM is comparable to as-rolled and annealed IN625 material. The samples machined from bulk specimens exhibit good tensile properties regardless of the contouring strategy due to the high depth of machining (5.5mm). However, for the near-net shaped specimens with only 2.1 mm machining of the surfaces, elongation is significantly affected by the contouring strategy. This is in such a manner that the contoured near-net shape parts show relatively 32% less elongation compared to the samples without any contour. Accordingly, multi-beam contouring is better to be avoided to reach tensile properties comparable to the wrought material after a shallow machining, despite the fact that it can lead to a relative smoother surface finish after EBM.

1 - 45 av 45
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf