SwePub - sökning: WFRF:(Gorbatov Oleg I.)

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1.	Gorbatov, Oleg I., et al. (författare) Role of magnetism in Cu precipitation in alpha-Fe 2013 Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 88:17, s. 174113- Tidskriftsartikel (refereegranskat)abstract The temperature-dependent solubility of Cu in alpha-Fe and initial stages of Cu precipitation are investigated in first-principles calculations and statistical thermodynamic and kinetic modeling based on ab initio effective interactions. We demonstrate that the weakening of the phase separation tendency with increasing temperature, especially close to the magnetic phase transition, is related to the strong dependence of the "chemical" interactions on the global magnetic state. At the same time, our calculations demonstrate that the vibrational contribution obtained in the quasiharmonic approximation is relatively small for temperatures near the Curie point. The results of Monte Carlo simulations of Cu solubility and clustering are in good agreement with experimental data.
2.	Gorbatov, Oleg I., et al. (författare) Effect of composition on antiphase boundary energy in Ni3Al based alloys : Ab initio calculations 2016 Ingår i: PHYSICAL REVIEW B. - 2469-9950. ; 93:22 Tidskriftsartikel (refereegranskat)abstract The effect of composition on the antiphase boundary (APB) energy of Ni-based L1(2)-ordered alloys is investigated by ab initio calculations employing the coherent potential approximation. The calculated APB energies for the {111} and {001} planes reproduce experimental values of the APB energy. The APB energies for the nonstoichiometric gamma' phase increase with Al concentration and are in line with the experiment. The magnitude of the alloying effect on the APB energy correlates with the variation of the ordering energy of the alloy according to the alloying element's position in the 3d row. The elements from the left side of the 3d row increase the APB energy of the Ni-based L1(2)-ordered alloys, while the elements from the right side slightly affect it except Ni. The way to predict the effect of an addition on the {111} APB energy in a multicomponent alloy is discussed.
3.	Chen, Xu, et al. (författare) Ductility deterioration induced by L21 phase in ferritic alloy through Ti addition 2023 Ingår i: Journal of Materials Research and Technology. - : Elsevier Editora Ltda. - 2238-7854. ; 25, s. 3273-3284 Tidskriftsartikel (refereegranskat)abstract Ductility deterioration induced by L21-Ni2AlTi precipitates in the aged ferritic alloys was examined systematically by using a combination of scanning transmission electron microscope (STEM), mechanical tests and first-principles thermodynamic calculations. The experimental studies revealed that the strength and hardness of the aged Fe–10Cr–5Ni–1Al–1Ti ferritic alloy containing B2–NiAl and L21-Ni2AlTi precipitates were higher than that of the aged Fe–10Cr–5Ni–1Al ferritic alloy containing NiAl precipitates, whereas the elongation-to-failure decreased dramatically from 9.3% to 0.3% indicating an obvious ductility deterioration due to the formation of L21-Ni2AlTi precipitates. This was also confirmed by the observation of fracture transition mode from dimpled failure to cleavage failure. The first-principles calculations, concerning the precipitate/matrix interface, were carried out to provide a theoretical analysis for the ductile–brittle transition by means of empirical ductility criteria ratios G/B and (C12–C44)/B as well as cleavage energy. The cleavage energy results indicated an intrinsic brittleness of the L21-Ni2AlTi phase and the L21-Ni2AlTi/BCC-Fe interface. Our analysis revealed that the intrinsic brittleness of L21-Ni2AlTi phase and L21-Ni2AlTi/BCC-Fe interface plays a vital role in determining the deformation behavior of the aged Fe–10Cr–5Ni–1Al–1Ti alloy.
4.	Delandar, Arash Hosseinzadeh, et al. (författare) End-member compounds of a 4-sublattice model of multicomponent BCC solid solutions 2018 Ingår i: Data in Brief. - : Elsevier. - 2352-3409. ; 20, s. 1018-1022 Tidskriftsartikel (refereegranskat)abstract 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].
5.	Gorbatov, Oleg I., et al. (författare) Effect of magnetism on the solubility of 3d elements in BCC iron : Results of first-principle investigations 2013 Ingår i: Physics of metals and metallography. - 0031-918X .- 1555-6190. ; 114:8, s. 642-653 Tidskriftsartikel (refereegranskat)abstract The methods of quantum-mechanical simulation have been used to study alloys of bcc iron with 3d transition metals in the ferromagnetic and paramagnetic states. It has been shown that the main factor that determines the solubility of the 3d elements is their electronic structure. The energy of the solution, mixing, and effective interatomic interactions vary regularly depending on the position of the element in the Periodic Table and on the magnetic state of the matrix. In some cases, depending on the magnetic state, changes in these quantities lead to the violation of the Hume-Rothery rules that determine the solubility of substitutional elements in alloys. The results obtained help us to understand the microscopic mechanisms that determine the solubility of alloying elements and their effect on the phase stability and structural state of steels.
6.	Gorbatov, Oleg I., et al. (författare) Effect of Ni and Mn on the formation of Cu precipitates in α-Fe 2015 Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 102, s. 11-14 Tidskriftsartikel (refereegranskat)abstract Decomposition in bcc Fe-Cu-Ni and Fe-Cu-Mn alloys is studied using statistical thermodynamics simulations with ab initio effective interactions. It is demonstrated that magnetic state strongly affects the effective interactions in these systems, substantially increasing phase separation tendency with magnetization. Simulations show that Ni is promoting precipitation of Cu by segregating to the precipitate matrix interface, while Mn produces almost no effect distributing more homogeneously in the system. The obtained distributions of Ni and Mn are in good agreement with experimental data.
7.	Gorbatov, Oleg I., et al. (författare) First-principles study of interactions between substitutional solutes in bcc iron 2016 Ingår i: Journal of Nuclear Materials. - : Elsevier. - 0022-3115 .- 1873-4820. ; 475, s. 140-148 Tidskriftsartikel (refereegranskat)abstract Using density functional theory based calculations, employing the locally self-consistent Green's function method and the projected augmented wave method, we develop a database of solute-solute interactions in dilute alloys of bcc Fe. Interactions within the first three coordination shells are computed for the ferromagnetic state as well as for the paramagnetic (disordered local moment) state of the iron matrix. The contribution of lattice relaxations to the defect interaction energy is investigated in the ferromagnetic state. Implications of the obtained results for modeling the phenomena of point defect clustering and phase precipitation in bcc Fe-based alloys and steel are discussed.
8.	Gorbatov, Oleg I., et al. (författare) Many-body mechanism of Guinier-Preston zones stabilization in Al–Cu alloys 2017 Ingår i: Scripta Materialia. - : Acta Materialia Inc. - 1359-6462 .- 1872-8456. ; 138, s. 130-133 Tidskriftsartikel (refereegranskat)abstract Thermodynamics and atomic structures of pre-precipitates in dilute Al–Cu alloys are studied using Metropolis Monte Carlo simulations with many-body effective cluster interactions that have been systematically derived from ab initio supercell calculations. We show that many-body interactions, including the contributions due to lattice relaxations around the solute atoms, are mainly responsible for the formation of metastable planar atomic arrangements known as Guinier-Preston zones. Interaction terms up to four-body clusters are shown to be necessary to correctly reproduce the structures and temperatures of pre-precipitation in Al–Cu solid solutions.
9.	Gorbatov, Oleg, et al. (författare) Magnetic exchange interactions in yttrium iron garnet : A fully relativistic first-principles investigation 2021 Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 104:17 Tidskriftsartikel (refereegranskat)abstract Magnetic isotropic and Dzyaloshinskii-Moriya interactions in yttrium iron garnet have been obtained byab initio fully relativistic calculations. The calculated coupling constants are in agreement with availableexperimental data. Using linear spin-wave theory, we are able to reproduce the experimental magnon spectrumincluding the spin-wave gap and stiffness. The way to calculate the exchange coupling constants using theKorringa-Kohn-Rostoker formalism for large magnetic systems such as complex oxides is discussed in detail.
10.	He, Shuang, et al. (författare) Effective interactions and atomic ordering in Ni-rich Ni-Re alloys 2016 Ingår i: Physical Review B Condensed Matter. - PRB : American Physical Society (APS). - 0163-1829 .- 1095-3795. ; 94:2 Tidskriftsartikel (refereegranskat)abstract Interatomic interactions and ordering in fcc Ni-rich Ni-Re alloys are studied by means of first-principles methods combined with statistical mechanics simulations based on the Ising Hamiltonian. First-principles calculations are employed to obtain effective chemical and strain-induced interactions, as well as ordering energies and enthalpies of formation of random and ordered Ni-Re alloys. Based on the nonmagnetic enthalpies of formation, we speculate that the type of ordering can be different in alloys with Re content less than 10 at.%. We demonstrate that effective chemical interactions in this system are quite sensitive to the alloy composition, atomic volume, and magnetic state. In statistical thermodynamic simulations, we have used renormalized interactions, which correctly reproduce ordering energies obtained in the direct total energy calculations. Monte Carlo simulations for Ni 0.91 Re 0.09 alloy show that there exists a strong ordering tendency of the (112 0) type leading to precipitation of the D1 a ordered structure at about 940 K. Our results for the atomic short-range order indicate, however, that the presently applied theory overestimates the strength of the ordering tendency compared to that observed in the experiment.
11.	He, Shuang, et al. (författare) First-principles-based statistical thermodynamic study of atomic interactions and phase stability in Ni-rich Ni-W alloys 2023 Ingår i: Calphad. - : Elsevier. - 0364-5916 .- 1873-2984. ; 82 Tidskriftsartikel (refereegranskat)abstract Atomic interactions and phase stability in Ni-rich Ni-W alloys have been investigated by using first-principles methods and statistical thermodynamic simulations. First-principles methods have been employed to explore lattice expansion, enthalpies of formation, atomic interactions, and ordering energies of ordered as well as random structures in Ni-rich Ni-W alloys with consideration of the corresponding temperature-dependent magnetic states. It is found that atomic interactions in Ni-rich Ni-W alloys depend on alloy composition, atomic volume, and magnetic state. Nevertheless, the magnetic state of Ni greatly affects the formation enthalpies, which leads to a diverse phase separation behavior at finite temperature in Ni-rich Ni-W alloys. By using atomic interactions that reproduce the ordering energies obtained in the direct total energy calculations, our statistical thermodynamic simulations of chemical short-range order results show that fcc-based ordered D1a, D022, and Pt2Mo phases can be observed in Ni-20 at.% W, Ni-25 at.% W, and Ni-33 at.% W alloys, respectively. Moreover, the short-range order diffuse intensity and atomic stacking for aforementioned ordered phases have been analyzed, the orderâ€“disorder transition behaviors have been also investigated in detail for the Ni-rich Ni-W alloys up to 35 at.% W with comparison of current experimental results. Both magnetic state and alloy composition have the potential to induce the formation of distinct ordered phases, offering promising avenues for designing Ni-based alloys. The methodologies we used in this study can be applied to investigate the atomic interactions as well as phase stability in other alloy systems.
12.	He, Shuang, et al. (författare) First-principles study of Re-W interactions and their effects on the mechanical properties of γ/γ' interface in Ni-based single-crystal alloys 2023 Ingår i: Materials Today Communications. - : Elsevier. - 2352-4928. ; 36 Tidskriftsartikel (refereegranskat)abstract The distribution of solutes and their interactions play a crucial role in determining the mechanical properties of the γ/γ′ interface in Ni-based single-crystal alloys. In this study, atomic interactions between Re and W and their alloying effects on the inter-phase cohesion of the γ/γ′ interface are investigated by first-principles calculations. Our results show that W atom exhibits a preference for partitioning into the γ phase, while the stability of the γ/γ′ interface can be enhanced due to the partitioning of W to the γ′ phase. Moreover, our results reveal that partitioned W atoms in the γ′ phase contribute to the strengthening of the γ/γ′ interface. Conversely, the dissolution of W atoms in the γ phase weakens the inter-phase cohesion. However, this detrimental effect can be mitigated by introducing of Re into the γ/γ′ interface. Partitioning of Re and W into separate phases yields minimal alterations in interaction energies, resulting in a notable enhancement of inter-phase cohesion when compared to the partitioning of Re and W within γ phase of the γ/γ′ interface. Additionally, the partitioning of solute atoms at the γ/γ′ interface leads to local lattice distortion and interfacial energy reduction, which contribute to the enhancement of inter-phase cohesion of the γ/γ′ interface. As a result, a model is proposed for interpretation of crack propagation at the γ/γ′ interface at the threshold region with the presence of tensile stress in Ni-based single-crystal alloys.
13.	He, Shuang, et al. (författare) Interactions and phase stability in Ni-rich Ni-W alloys Annan publikation (övrigt vetenskapligt/konstnärligt)abstract Interatomic interactions and phase transformation in Ni-rich Ni-W alloys are investigated using rst-principlesmethods and statistical thermodynamics simulations. The formation enthalpies of fcc and bcc random as wellas some fcc-based ordered structures are determined in the ferromagnetic and nonmagnetic states. The effective interactions are calculated in supercell ab initio calculations and using screened generalized perturbation method(SGPM). We find the stable fcc-based ordered structures are D1a, DO22 and Pt2Mo phases and they can be observed in the Ni-25 at.% W, Ni-25 at.% W and Ni-33 at.% W alloys, respectively. The calculated atomic short-range order results are in reasonable agreement with experiments and other theoretical investigations.
14.	Jacobsson, Adam, et al. (författare) Efficient parameterisation of non-collinear energy landscapes in itinerant magnets 2022 Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12 Tidskriftsartikel (refereegranskat)abstract Magnetic exchange interactions determine the magnetic groundstate, as well as magnetic excitations of materials and are thus essential to the emerging and fast evolving fields of spintronics and magnonics. The magnetic force theorem has been used extensively for studying magnetic exchange interactions. However, short-ranged interactions in itinerant magnetic systems are poorly described by this method and numerous strategies have been developed over the years to overcome this deficiency. The present study supplies a fully self-consistent method for systematic investigations of exchange interactions beyond the standard Heisenberg model. In order to better describe finite deviations from the magnetic ground state, an extended Heisenberg model, including multi-spin interactions, is suggested. Using cross-validation analysis, we show that this extended Heisenberg model gives a superior description for non-collinear magnetic configurations. This parameterisation method allows us to describe many different itinerant magnetic systems and can be useful for high-throughput calculations.
15.	Johansson, Gustav, et al. (författare) First-principles investigation of the (CrMnFeNi)1-xCox (0≤x≤0.2) alloy Annan publikation (övrigt vetenskapligt/konstnärligt)abstract The (CrMnFeNi)1−xCox high-entropy alloy is investigated for 0≤x≤0.2 by density functional theory calculations. All calculations are performed in theparamagnetic fcc-phase. It is shown that the exact muffin-tin orbital formalismcombined with the coherent potential approximation can reproduce experimentalvalues of equilibrium volume and magnetic moment. The thermal expansion isinvestigated using the Debye-Grüneisen model. Experimental results of the thermalexpansion coefficient and lattice parameter are reproduced only when including bothelectronic and magnetic contribution to the free energy. The investigated alloysshow anti-invar behaviour with a large increase in thermal expansion parameter withtemperature. For reduced Co-concentrations, the thermal expansion coefficient andlattice parameter are seen to increase, leading to slightly lower values of the elasticconstants. The stability of the alloys is discussed in terms of stacking fault energy andmixing energy.
16.	Johansson, Gustav, et al. (författare) Theoretical investigation of magnons in Fe-Ga alloys 2023 Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 108:18 Tidskriftsartikel (refereegranskat)abstract Fe-Ga alloys show an unusually large increase in magnetostriction compared to pure Fe and are one of the most interesting Fe-based alloys for this reason. However, the origin of the large magnetostriction and its relation to the chemical ordering on the underlying bcc phase is still under debate. To gain further understanding of the extraordinary magnetoelastic characteristics of this system, we investigate the effect of Ga-concentration and ordering on the spin-wave spectra and stiffness. The magnetic interactions in the Fe-Ga alloys are obtained by ab initio electronic structure calculations and the magnon spectra are modeled using atomistic spin dynamics modeling. Our results agree with available experimental data and show softening of the magnon modes with increasing Ga-concentration and a strong reduction of the spin-wave stiffness due to atomic ordering.
17.	Liu, Ye, et al. (författare) First-principles investigation on the thermodynamic and mechanical properties of Y4Zr3O12 and Y2Ti2O7 oxides in ferritic alloy under helium environment 2024 Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854. ; 29, s. 1872-1886 Tidskriftsartikel (refereegranskat)abstract This study investigates the thermodynamic and mechanical properties of Y4Zr3O12 and Y2Ti2O7 oxides in ferritic alloys with and without Helium utilizing a systematic first-principles approach. Firstly, the atomic arrangement of Y and Zr atoms at cation 18f sites in δ-(Y–Zr–O) oxide is identified, while it is found that Y4Zr3O12 exhibits a more robust formation tendency than Y2Ti2O7. Furthermore, it is noted that both Y4Zr3O12 and Y2Ti2O7 oxides demonstrate a prior ability to trap Helium compared to the bcc-Fe matrix, which leads to a substantial enhancement on the stiffness of both oxides. The elastic moduli of both Y4Zr3O12 and Y2Ti2O7 oxide exhibit a gradual increase with the growing Helium concentration. As a result, the enhanced shear modulus of oxides and sustained shear modulus of the bcc-Fe matrix collectively contribute to the overall strength of ferritic alloys under Helium environments. The findings in this work propose valuable insights for guiding critical strategies in the design of high-performance oxide-dispersion-strengthened ferritic alloys, particularly for applications in Helium environments.
18.	Liu, Ye, et al. (författare) In-situ formation of AlN nanoparticles in NiAl-strengthened ferritic alloy with enhanced high-temperature mechanical properties via SLM fabrication 2024 Ingår i: Materials Science & Engineering. - : Elsevier Ltd. - 0921-5093 .- 1873-4936. ; 899 Tidskriftsartikel (refereegranskat)
19.	Neding, Benjamin, et al. (författare) In Situ Bulk Observations and Ab Initio Calculations Revealing the Temperature Dependence of Stacking Fault Energy in Fe–Cr–Ni Alloys 2021 Ingår i: Metallurgical and Materials Transactions. A. - : Springer Nature. - 1073-5623 .- 1543-1940. ; 52:12, s. 5357-5366 Tidskriftsartikel (refereegranskat)abstract The dependence of stacking fault energy (γSFE) on temperature in austenitic Fe–Cr–Ni alloy powders was investigated by in situ high energy synchrotron X-ray diffraction and ab initio calculations in the temperature range from −45 °C to 450 °C. The X-ray diffraction peak positions were used to determine the stacking fault probability and subsequently the temperature dependence of γSFE. The effect of temperature on the diffraction peak positions was found to be mainly reversible; however, recovery of dislocations occurred above about 200 °C, which also gave an irreversible contribution. Two different ab initio-based models were evaluated with respect to the experimental data. The different predictions of the models can be explained by their respective treatment of the magnetic moments for Cr and Ni, which is critical for the alloy compositions investigated. Ab initio calculations, taking longitudinal spin fluctuations (LSF) into consideration within the quasi-classical phenomenological model, predict a temperature dependence of γSFE in good agreement with the experimentally evaluated trend of increasing γSFE with increasing temperature: \|ΔγSFE/ΔT\|=0.05mJm−2/K. The temperature effect on γSFE is similar for all three investigated alloys: Fe–18Cr–15Ni, Fe–18Cr–17Ni, Fe–21Cr–16Ni (wt pct), while their room temperature γSFE are evaluated to be 22, 25, 20 mJ m−2, respectively.
20.	Serikov, V. V., et al. (författare) Formation of solid solutions of gallium in Fe-Cr and Fe-Co alloys : Mossbauer studies and first-principles calculations 2014 Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 614, s. 297-304 Tidskriftsartikel (refereegranskat)abstract Investigation of Ga influence on the structure of Fe-Cr and Fe-Co alloys was performed with the use of Mossbauer spectroscopy and X-ray diffraction methods. The experimental results are compared with results of first-principles calculations of the mixing and solubility energies for Ga in an Fe-X (X = Co, Cr) alloy both in ferromagnetic and paramagnetic states. It is shown that Ga mainly goes into the solid solutions of the base alloys. In the alloys of the Fe-Cr system, doping with Ga handicaps the decomposition of solid solutions, observed in the binary alloys, and increases its stability. In the alloys with Co, Ga also favors the uniformity of solid solutions. The results of the first-principles calculations testify in favor of a preferable dissolution of Ga in the FeCo regions of a multicomponent structure rather than FeCr regions, both types of regions being in the ferromagnetic state at the temperature of annealing. The analysis of Mossbauer experiments gives some grounds to conclude that if, owing to liquation, clusterization, or initial stages of phase separation, there exist regions enriched in iron, some amount of Ga atoms prefer to enter the nearest surroundings of iron atoms, thus forming binary Fe-Ga regions (or phases).
21.	Shmakov, I. G., et al. (författare) Short-range order formation in Fe-Co alloys: NMR study and first-principles calculations 2019 Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 782, s. 1008-1014 Tidskriftsartikel (refereegranskat)abstract The short/long-range order formation in Fe1-x-Cox (x < 0.3) alloys has been studied by the nuclear magnetic resonance (NMR) technique, as well as ab initio based atomistic simulation. The NMR measurements show up the formation of a certain short-range order (SRO) in dilute limit above the Curie temperature TC and of the D03-type SRO (with the dominance of 3rd Co-Co nearest neighbors) in the concentration range 0.2 < x < 0.3 after quenching and subsequent annealing in the ferromagnetic state. The results of Monte Carlo simulations of binary Fe-Co alloys with ab initio interatomic interactions predict SRO in agreement with the experiment for small concentrations of Co (CCo< 0.1), while the B2-type ordering is preferable in binary alloy in the ferromagnetic state. We demonstrate that the presence of point defects (vacancies, interstitial) can change essentially the ordering in alloys with the Co content 20-30% and result in the D03-type SRO formation in a reasonable agreement with the experiment.
22.	Stroev, A.Yu., et al. (författare) Ab-initio based modeling of precipitation in Al–(Sc,Zr) alloy. Formation and stability of a core–shell structure 2023 Ingår i: Computational materials science. - : Elsevier. - 0927-0256 .- 1879-0801. ; 218 Tidskriftsartikel (refereegranskat)abstract Statistical alloy theory based on the Master Equation approach with ab initio calculated interatomic interactions is employed to investigate the growth of precipitates at the early stages of solid solution decomposition, as well as the dissolution of small precipitates during the coarsening stage, upon simulated annealing of ternary Al–Sc–Zr alloys. We show, in agreement with previous studies, that the Zr alloying to Al–Sc alloys promotes the formation of core–shell nanoparticles whose structure is found to be very sensitive to the parameters characterizing the solute diffusion rates in the alloy. We demonstrate that the core–shell structure of precipitates slows down the dissolution of small particles, thus hampering the microstructure coarsening at elevated temperatures.
23.	Tan, Qiankun, et al. (författare) Hydrogen-enhanced decohesion mechanism of the Ni-Ni3X interfaces in precipitation-hardened Ni-based alloys 2023 Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 963 Tidskriftsartikel (refereegranskat)abstract Ni and its alloys are susceptible to hydrogen embrittlement. In this study, we investigate the phenomenon of hydrogen-enhanced decohesion at inter-phase interfaces in precipitation-hardened Ni-based alloys using a systematic first-principles approach. We demonstrate that hydrogen atoms primarily prefer to localize at the Ni3Al phase in the Ni/Ni3Al interface, while they tend to be trapped by Ni in the Ni/Ni3Nb interface. Our findings reveal that hydrogen induces inter-phase embrittlement in both the Ni/Ni3Al and Ni/Ni3Nb interfaces. Moreover, we show that the hydrogen-enhanced decohesion at these interfaces is influenced by various factors such as hydrogen pressure, hydrogen content, temperature, and strain. Finally, we discuss in detail the hydrogen-enhanced decohesion mechanisms at the Ni/Ni3Al and Ni/Ni3Nb interfaces, including their electronic structures, energy landscape of hydrogen at trapping sites, and schematics of crack propagation.
24.	Tian, Ye, et al. (författare) Deformation Microstructure and Deformation-Induced Martensite in Austenitic Fe-Cr-Ni Alloys Depending on Stacking Fault Energy 2017 Ingår i: Metallurgical and Materials Transactions. A. - : Springer. - 1073-5623 .- 1543-1940. ; 48A:1, s. 1-7 Tidskriftsartikel (refereegranskat)abstract The deformation microstructure of austenitic Fe-18Cr-(10-12)Ni (wt pct) alloys with low stacking fault energies, estimated by first-principles calculations, was investigated after cold rolling. The E >-martensite was found to play a key role in the nucleation of alpha'-martensite, and at low SFE, E > formation is frequent and facilitates nucleation of alpha' at individual shear bands, whereas shear band intersections become the dominant nucleation sites for alpha' when SFE increases and mechanical twinning becomes frequent.
25.	Xiong, Sangqi, et al. (författare) A combined machine learning and density functional theory study of binary Ti-Nb and Ti-Zr alloys: Stability and Young’s modulus 2020 Ingår i: Computational materials science. - : Elsevier. - 0927-0256 .- 1879-0801. ; 184 Tidskriftsartikel (refereegranskat)abstract The multicomponent Ti alloys, specifically the β-phase, have experienced a strong growth over the last decades, due to their outstanding properties of ultra-high strength and low Young’s modulus. These properties play a significant role in many aerospace and biomedical applications. Selection and optimization of multicomponent alloys is challenging due to the vast chemical and compositional space. Here we investigate the use of machine learning techniques informed by density functional calculations to guide the selection of Nb- and Zr-based Ti binary alloys. From the cubic structures obtained from high throughput calculations and literature, we identify several structures with Young’s moduli below 40 GPa. The multivariant decision tree methods provide efficient surrogate models to identify structure variables have high influences on the energetic stability and Young’s modulus. We implement a workflow of incorporating DFT provided results and machine learning method to explore the chemical and composition space of other binary and multicomponent alloys, to eventually accelerate the material design via taking advantages of identified key variables.
26.	Zhang, Lin, et al. (författare) Cr-promoted formation of B2+L21 composite nanoprecipitates and enhanced mechanical properties in ferritic alloy 2023 Ingår i: Acta Materialia. - : Elsevier. - 1359-6454 .- 1873-2453. ; 243 Tidskriftsartikel (refereegranskat)abstract The critical role of Cr on nanoprecipitates and the mechanical property of Fe-Ni-Al-Mn ferritic steel were systematically studied in this research. The two types of nanoprecipitates in the Cr added alloy were characterized through a combination of aberration-corrected scanning transmission electron microscopy and atom probe tomography techniques. The atomic-scale structure and chemistry analysis reveal that fine globular-shaped precipitates have a B2-structure, while coarse elongated precipitates have B2+L21 composite structures. The first-principles calculations reveal that the segregation of Cr at the L21/bcc interface reduces the interface and strain energy for the nucleation of the L21-type phase. With the increasing precipitate size, the B2 structure is gradually transformed to L21 to reduce elastic strain, thereby promoting the formation of B2+L21 composite nanoprecipitate. The addition of 10 wt% Cr results in an increase of ∼275 MPa in yield strength without obvious loss of ductility. The effect of Cr on the strength mechanisms were quantitatively analyzed, revealing that the strength of the ferritic alloy mainly improved by the formation of B2+L21 composite nanoprecipitate, which is more effective than solid solution strengthening.

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