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Delandar, A. H., Gorbatov, O. I., Selleby, M., Gornostyrev, Y. N. N. & Korzhavyi, P. . (2018). Ab-initio based search for late blooming phase compositions in iron alloys. Journal of Nuclear Materials, 509, 225-236
Open this publication in new window or tab >>Ab-initio based search for late blooming phase compositions in iron alloys
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2018 (English)In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 509, p. 225-236Article in journal (Refereed) Published
Abstract [en]

We present a systematic analysis, based on ab initio calculations, of concentrated solute arrangements and precipitate phases in Fe-based alloys. The input data for our analysis are the calculated formation and interaction energies of point defects in the iron matrix, as well as the energies of ordered compounds that represent end-members in the 4-sublattice compound energy model of a multicomponent solid solution of Mg, Al, Si, P, S, Mn, Ni, and Cu elements and also vacancies in bcc Fe. The list of compounds also includes crystal structures obtained by geometric relaxation of the end-member compounds that in the cubic structure show weak mechanical instabilities (negative elastic constants) and also the G-phase Mn-6(Ni,Fe)(16)(Si,P)(7) having a complex cubic structure. A database of calculated thermodynamic properties (crystal structure, molar volume, enthalpy of formation, and elastic constants) of the most stable late-blooming-phase candidates is thus obtained. The results of this ab initio based theoretical analysis compare well with the recent experimental observations and predictions of thermodynamic calculations employing Calphad methodology.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Iron alloys, ab initio calculations, Solute clusters, Precipitate phases
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:kth:diva-234563 (URN)10.1016/j.jnucmat.2018.06.028 (DOI)000442483300026 ()2-s2.0-85049458637 (Scopus ID)
Funder
Swedish Nuclear Fuel and Waste Management Company, SKBVINNOVA
Note

QC 20180919

Available from: 2018-09-19 Created: 2018-09-19 Last updated: 2018-09-19Bibliographically approved
Lousada, C. M., Johansson, A. J. & Korzhavyi, P. . (2018). Adsorption of Hydrogen Sulfide, Hydrosulfide and Sulfide at Cu(110) - Polarizability and Cooperativity Effects. First Stages of Formation of a Sulfide Layer. ChemPhysChem, 19(17), 2159-2168
Open this publication in new window or tab >>Adsorption of Hydrogen Sulfide, Hydrosulfide and Sulfide at Cu(110) - Polarizability and Cooperativity Effects. First Stages of Formation of a Sulfide Layer
2018 (English)In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 19, no 17, p. 2159-2168Article in journal (Refereed) Published
Abstract [en]

Understanding the surface site preference for single adsorbates, the interactions between adsorbates, how these interactions affect surface site specificity in adsorption and perturb the electronic states of surfaces is important for rationalizing the structure of interfaces and the growth of surface products. Herein, using density functional theory (DFT) calculations, we investigated the adsorption of H2S, HS and, S onto Cu(110). The surface site specificity observed for single adsorbates can be largely affected by the presence of other adsorbates, especially S that can affect the adsorption of other species even at distances of 13 Å. The large supercell employed with a surface periodicity of (6×6) allowed us to safely use the Helmholtz method for the determination of the dipole of the surface-adsorbate complex at low adsorbate coverages. We found that the surface perturbation induced by S can be explained by the charge transfer model, H2S leads to a perturbation of the surface that arises mostly from Pauli exclusion effects, whereas HS shows a mix of charge transfer and Pauli exclusion effects. These effects have a large contribution to the long range adsorbate-adsorbate interactions observed. Further support for the long range adsorbate-adsorbate interactions are the values of the adsorption energies of adsorbate pairs that are larger than the sum of the adsorption energies of the single adsorbates that constitute the pair. This happens even for large distances and thus goes beyond the H-bond contribution for the H-bond capable adsorbate pairs. Exploiting this knowledge we investigated two models for describing the first stages of growth of a layer of S-atoms at the surface: the formation of islands versus the formation of more homogeneous surface distributions of S-atoms. We found that for coverages lower than 0.5 ML the S-atoms prefer to cluster as islands that evolve to stripes along the [1 (Formula presented.) 0] direction with increasing coverage. At 0.5 ML a homogeneous distribution of S-atoms becomes more stable than the formation of stripes. For the coverage equivalent to 1 ML, the formation of two half-monolayers of S-atoms that disrupt the Cu−Cu bonds between the first and second layer is more favorable than the formation of 1 ML homogeneous coverage of S-atoms. Here the S−Cu bond distances and geometries are reminiscent of pyrite, covellite, and to some extent chalcocite. The small energy difference of ≈0.1 eV that exists between this structure and the formation of 1 ML suggests that in a real system at finite temperature both structures may coexist leading to a structure with even lower symmetry.

Place, publisher, year, edition, pages
Wiley-VCH Verlag, 2018
Keywords
adsorbate-adsorbate interactions, copper sulfide growth, hydrogen sulfide, polarizability, sulfur adsorption
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-236702 (URN)10.1002/cphc.201800246 (DOI)000443680500008 ()2-s2.0-85052734894 (Scopus ID)
Funder
Swedish Nuclear Fuel and Waste Management Company, SKB
Note

Export Date: 22 October 2018; Article; CODEN: CPCHF; Correspondence Address: Lousada, C.M.; Department of Materials Science and Engineering, KTH Royal Institute of Technology SE-Sweden; email: cmlp@kth.se; Funding details: SKB, Svensk Kärnbränslehantering; Funding details: KTH, Kungliga Tekniska Högskolan; Funding text: Financial support from the Swedish Nuclear Fuel and Waste Management Company (SKB) is gratefully acknowledged. The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC): at the Center for High Performance Computing at the KTH – Royal Institute of Technology (PDC). QC 20181112

Available from: 2018-11-12 Created: 2018-11-12 Last updated: 2018-11-12Bibliographically approved
Walbrühl, M., Blomqvist, A. & Korzhavyi, P. . (2018). Atomic diffusion in liquid nickel: First-principles modeling. Journal of Chemical Physics, 148(24), Article ID 244503.
Open this publication in new window or tab >>Atomic diffusion in liquid nickel: First-principles modeling
2018 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 148, no 24, article id 244503Article in journal (Refereed) Published
Abstract [en]

Self- and impurity diffusion coefficients are assessed in the liquid nickel system by the fundamental ab initio molecular dynamics approach. The impurity diffusion coefficients in the Ni-X systems (X=C, Co, N, Nb, Ta, Ti, W) are mostly not available in the current literature. The simulations are performed at four temperatures, in the range from 1903 to 2303 K, which allows to extract activation energies and frequency factors for the temperature dependent diffusion coefficient assuming an Arrhenius-type behavior in the liquid. In addition to the temperature dependence, the concentration-dependent impurity diffusion was investigated for the Ni-Co system. The data are of relevance for the development of the state-of-the art Ni-based superalloys and alternative binder systems in cemented carbides. The obtained theoretical results are in very good agreement with the limited experimental data for the diffusion in liquid Ni systems.

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2018
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-232410 (URN)10.1063/1.5026348 (DOI)000437190300069 ()29960348 (PubMedID)2-s2.0-85049023346 (Scopus ID)
Note

QC 20180726

Available from: 2018-07-26 Created: 2018-07-26 Last updated: 2018-07-26Bibliographically approved
Delandar, A. H., Gorbatov, O. I., Selleby, M., Gornostyrev, Y. N. & Korzhavyi, P. . (2018). End-member compounds of a 4-sublattice model of multicomponent BCC solid solutions. Data in Brief, 20, 1018-1022
Open this publication in new window or tab >>End-member compounds of a 4-sublattice model of multicomponent BCC solid solutions
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2018 (English)In: Data in Brief, E-ISSN 2352-3409, Vol. 20, p. 1018-1022Article in journal (Refereed) Published
Abstract [en]

The article presents ab initio calculated properties (total energies, lattice parameters, and elastic properties) for the complete set of 1540 end-member compounds within a 4-sublattice model of Fe-based solid solutions. The compounds are symmetry-distinct cases of integral site occupancy for superstructure Y (space group #227, type LiMgPdSn) chosen to represent the ordered arrangements of solvent atoms (Fe), solute atoms (Fe, Mg, Al, Si, P, S, Mn, Ni, Cu), and vacancies (Va) on the sites of a body-centered cubic lattice. The model is employed in the research article “Ab-initio based search for late blooming phase compositions in iron alloys” (Hosseinzadeh et al., 2018) [1].

Place, publisher, year, edition, pages
Elsevier Inc., 2018
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-236663 (URN)10.1016/j.dib.2018.08.086 (DOI)000450242200152 ()2-s2.0-85053047195 (Scopus ID)
Note

Export Date: 22 October 2018; Article; Correspondence Address: Korzhavyi, P.A.; Department of Materials Science and Engineering, KTH Royal Institute of TechnologySweden; email: pavelk@kth.se; Funding details: VINNOVA; Funding details: SKB, Svensk Kärnbränslehantering; Funding details: NSC; Funding details: 14, Minobrnauka, Ministry of Education and Science of the Russian Federation; Funding details: Z50.31.0043, Minobrnauka, Ministry of Education and Science of the Russian Federation; Funding details: Y26.31.0005, Minobrnauka, Ministry of Education and Science of the Russian Federation; Funding details: KTH, Kungliga Tekniska Högskolan; Funding details: K2–2017-080; Funding details: 211; Funding text: This work has been supported by Svensk Kärnbränslehantering AB, the Swedish Nuclear Fuel and Waste Management Company (SKB). The study has been carried out at the VINNEX center Hero-m financed by the Swedish Governmental Agency for Innovation Systems (VINNOVA), Swedish Industry , and the KTH Royal Institute of Technology . The computations were partly done on resources provided by the Swedish National Infrastructure for Computing (SNIC) at the National Supercomputer Center (NSC) in Linköping and at the Center for High Performance Computing (PDC) in Stockholm, Sweden. Ab initio calculations were carried out with support provided by the Ministry of Education and Science of the Russian Federation , Grants no. 14.Y26.31.0005 and 14.Z50.31.0043 . Analysis of theoretical data was supported by the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST “MISIS” (No. K2–2017-080) implemented by a governmental decree dated 16 March 2013, No 211. Transparency document. QC 2018113

Available from: 2018-11-13 Created: 2018-11-13 Last updated: 2018-12-07Bibliographically approved
Lousada, C. M. & Korzhavyi, P. . (2018). First stages of oxide growth on Al(1 1 0) and core-level shifts from density functional theory calculations. Applied Surface Science, 441, 174-186
Open this publication in new window or tab >>First stages of oxide growth on Al(1 1 0) and core-level shifts from density functional theory calculations
2018 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 441, p. 174-186Article in journal (Refereed) Published
Abstract [en]

The formation of islands of O-atoms is the dominant mode of growth of the oxide in the first stages of oxidation of Al(1 1 1). It is however unknown if a similar mechanism exists for other low index surfaces of Al. We performed a density functional theory (DFT) and ab initio molecular dynamics investigation of the first stages of the oxidation of Al(1 1 0) using two distinct models: a homogeneous surface disposition of O-atoms; and a model where the O-atoms are close-spaced forming clusters or islands. We investigated the surface reactions with oxygen up to a coverage of 2 ML and found that for both models the adsorption energy per dissociating O2(g) becomes more negative with increasing coverage. Our results show that for coverages up to 1.25 ML the oxide forms clusters or islands while for coverages higher than 1.5 ML the oxide covers the surface homogeneously. This is because the O-atoms bind preferably to neighboring sites even at the minimum coverage. With increasing coverage, the clusters of O start to form stripes along the [1 1¯ 0] direction. The work function (ϕ) of the surface decreases when going from bare Al(1 1 0) to up to 1 ML coverage of O-atoms, but for coverages of 1.25 ML and higher, ϕ increases. The Al 2p surface core level shifts (SCLS) shift towards higher binding energies with increasing surface coverage of O-atoms and start to approach the values of Al 2p in Al2O3 already at a coverage of 2ML. A relation between the SCLS and the coordination number of Al to O-atoms was made. The Al 2p SCLS increases with increasing coordination to O-atoms, for single, twofold and three-fourfold coordinated cations. For the O-atoms that terminate the surface at the short-bridge sites, the SCLS of O 1s, is largely affected by the proximity to other O-atoms. These results demonstrate that the cooperative effects between surface bound O-atoms have important roles in the mechanism of growth of the oxide at Al(1 1 0), and similarly to what happens for Al(1 1 1), the initial oxidation of Al(1 1 0) proceeds via the formation of islands of O-atoms.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Al(1 1 0), Aluminum, DFT, Oxidation, Oxygen adsorption, Oxygen islands
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-227568 (URN)10.1016/j.apsusc.2018.01.246 (DOI)000427816400021 ()2-s2.0-85041747539 (Scopus ID)
Funder
Swedish Foundation for Strategic Research , RMA11-0090
Note

QC 20180517

Available from: 2018-05-17 Created: 2018-05-17 Last updated: 2018-05-17Bibliographically approved
Delandar, A. H., Sandström, R. & Korzhavyi, P. . (2018). The Role of Glide during Creep of Copper at Low Temperatures. METALS, 8(10), Article ID 772.
Open this publication in new window or tab >>The Role of Glide during Creep of Copper at Low Temperatures
2018 (English)In: METALS, ISSN 2075-4701, Vol. 8, no 10, article id 772Article in journal (Refereed) Published
Abstract [en]

Copper canister will be used in Scandinavia for final storage of spent nuclear fuel. The copper will be exposed to temperatures of up to 100 degrees C. The creep mechanism at near ambient temperatures has been assumed to be glide of dislocations, but this has never been verified for copper or other materials. In particular, no feasible mechanism for glide based static recovery has been proposed. To attack this classical problem, a glide mobility based on the assumption that it is controlled by the climb of the jogs on the dislocations is derived and shown that it is in agreement with observations. With dislocation dynamics (DD) simulations taking glide but not climb into account, it is demonstrated that creep based on glide alone can reach a quasi-stationary condition. This verifies that static recovery can occur just by glide. The DD simulations also show that the internal stress during creep in the loading direction is almost identical to the applied stress also directly after a load drop, which resolves further classical issues.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
creep, dislocation dynamics, glide, internal stress
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-239112 (URN)10.3390/met8100772 (DOI)000448658700036 ()2-s2.0-85054663275 (Scopus ID)
Note

QC 20181120

Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2018-11-20Bibliographically approved
Li, Y., Korzhavyi, P. ., Sandström, R. & Lilja, C. (2017). Impurity effects on the grain boundary cohesion in copper. Physical Review Materials, 1(7), Article ID 070602.
Open this publication in new window or tab >>Impurity effects on the grain boundary cohesion in copper
2017 (English)In: Physical Review Materials, ISSN 2475-9953, Vol. 1, no 7, article id 070602Article in journal (Refereed) Published
Abstract [en]

Segregated impurities at grain boundaries can dramatically change the mechanical behavior of metals, while the mechanism is still obscure in some cases. Here, we suggest a unified approach to investigate segregation and its effects on the mechanical properties of polycrystalline alloys using the example of 3sp impurities (Mg, Al, Si, P, or S) at a special type Sigma 5(310)[001] tilt grain boundary in Cu. We show that for these impurities segregating to the grain boundary, the strain contribution to the work of grain boundary decohesion is small and that the chemical contribution correlates with the electronegativity difference between Cu and the impurity. The strain contribution to the work of dislocation emission is calculated to be negative, while the chemical contribution is calculated to be always positive. Both the strain and chemical contributions to the work of dislocation emission generally become weaker with the increasing electronegativity from Mg to S. By combining these contributions together, we find, in agreement with experimental observations, that a strong segregation of S can reduce the work of grain boundary separation below the work of dislocation emission, thus embrittling Cu, while such an embrittlement cannot be produced by a P segregation because it lowers the energy barrier for dislocation emission relatively more than for work separation.

Place, publisher, year, edition, pages
American Physical Society, 2017
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-221014 (URN)10.1103/PhysRevMaterials.1.070602 (DOI)000418772500001 ()
Funder
Swedish Nuclear Fuel and Waste Management Company, SKBSwedish Foundation for Strategic Research
Note

QC 20180115

Available from: 2018-01-15 Created: 2018-01-15 Last updated: 2018-01-15Bibliographically approved
Gorbatov, O., Gornostyrev, Y. N. & Korzhavyi, P. . (2017). Many-body interactions in the Al–Cu system. Data in Brief, 15, 770-774
Open this publication in new window or tab >>Many-body interactions in the Al–Cu system
2017 (English)In: Data in Brief, E-ISSN 2352-3409, Vol. 15, p. 770-774Article in journal (Refereed) Published
Abstract [en]

The article contains computational data of many-body interactions in Al–Cu alloys, obtained using PAW-VASP calculations. Pairwise, three-site, and four-site interactions are presented. Mentioned data are relevant to the research article “Many-body mechanism of Guinier-Preston zones stabilization in Al–Cu alloys”.

Place, publisher, year, edition, pages
Elsevier Inc., 2017
National Category
Biophysics
Identifiers
urn:nbn:se:kth:diva-227125 (URN)10.1016/j.dib.2017.10.002 (DOI)2-s2.0-85032955869 (Scopus ID)
Note

QC 20180508

Available from: 2018-05-08 Created: 2018-05-08 Last updated: 2018-05-08Bibliographically approved
Kar'kin, I. N., Kar'kina, L. E., Korzhavyi, P. . & Gornostyrev, Y. N. N. (2017). Monte Carlo Simulation of the Kinetics of Decomposition and the Formation of Precipitates at Grain Boundaries of the General Type in Dilute BCC Fe-Cu Alloys. Physics of the solid state, 59(1), 106-113
Open this publication in new window or tab >>Monte Carlo Simulation of the Kinetics of Decomposition and the Formation of Precipitates at Grain Boundaries of the General Type in Dilute BCC Fe-Cu Alloys
2017 (English)In: Physics of the solid state, ISSN 1063-7834, E-ISSN 1090-6460, Vol. 59, no 1, p. 106-113Article in journal (Refereed) Published
Abstract [en]

The kinetics of decomposition of a polycrystalline Fe-Cu alloy and the formation of precipitates at the grain boundaries of the material have been investigated theoretically using the atomistic simulation on different time scales by (i) the Monte Carlo method implementing the diffusion redistribution of Cu atoms and (ii) the molecular dynamics method providing the atomic relaxation of the crystal lattice. It has been shown that, for a small grain size (D similar to 10 nm), the decomposition in the bulk of the grain is suppressed, whereas the copper-enriched precipitates coherently bound to the matrix are predominantly formed at the grain boundaries of the material. The size and composition of the precipitates depend significantly on the type of grain boundaries: small precipitates (1.2-1.4 nm) have the average composition of Fe-40 at % Cu and arise in the vicinity of low-angle grain boundaries, while larger precipitates that have sizes of up to 4 nm and the average composition of Fe-60 at % Cu are formed near grain boundaries of the general type and triple junctions.

Place, publisher, year, edition, pages
MAIK NAUKA/INTERPERIODICA/SPRINGER, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-205165 (URN)10.1134/S1063783417010140 (DOI)000394984600017 ()2-s2.0-85013276846 (Scopus ID)
Note

QC 20170412

Available from: 2017-04-12 Created: 2017-04-12 Last updated: 2017-11-29Bibliographically approved
Li, Y. & Korzhavyi, P. . (2017). Physical and chemical properties of Cu(I) compounds with O and/or H. Dalton Transactions, 46(2), 529-538
Open this publication in new window or tab >>Physical and chemical properties of Cu(I) compounds with O and/or H
2017 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 46, no 2, p. 529-538Article in journal (Refereed) Published
Abstract [en]

The electronic structure and chemical bonding of Cu(I) compounds with O and/or H are investigated using ab initio calculations based on density functional theory. A hybrid functional PBE0 is employed, which accurately reproduces an experimental band gap of cuprite Cu2O. Cuprous hydroxide CuOH (cuprice) is found to be an indirect band gap semiconductor. Depending on the bond network configuration of CuOH, its band gap is found to vary between 2.73 eV and 3.03 eV. The presence of hydrogen in CuOH has little effect on the character of Cu-O bonds, as compared to Cu2O, but lowers the energy levels of the occupied states upon O- H bond formation. The bonding charge density and electron localization function calculations reveal that a closed-shell Cu-Cu interaction takes place in Cu2O and CuOH between the neighbouring Cu cations belonging to different bond networks. Besides, three structures of cuprous hydride CuH are investigated. We find that the halite structure of CuH can be stabilized at high pressure (above 32 GPa) while wurtzite is the most stable structure of CuH at ambient pressure. The H-H interaction contributes to the dynamical stabilization of the halite structure. The wurtzite and sphalerite structures of CuH are predicted to be semiconducting with small band gaps, while the halite structure is calculated to be metallic.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-201238 (URN)10.1039/c6dt04376c (DOI)000391726400025 ()2-s2.0-85008512148 (Scopus ID)
Note

QC 20170216

Available from: 2017-02-16 Created: 2017-02-16 Last updated: 2017-11-29Bibliographically approved
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