The Bain path of paramagnetic Fe-Cr based alloys

Al-Zoubi, Noura; Johansson, Börje; Nilson, G.; Vitos, Levente

doi:10.1063/1.3603024

Cited by 19 publications

(12 citation statements)

References 37 publications

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“…The kinetic energy cutoff was 400 eV, and the Brillouin zone was sampled by a 5 × 3 × 1 Γ-centered k-points mesh following the Monkhorst-Pack method [27]. As for magnetism of the paramagnetic austenitic phase γ-Fe, there are different ways to deal with the directions of the magnetic moments, including disregard [28][29][30], setting spin according to the ferromagnetic phase [31], and adopting the disordered local moments model [32][33][34]. Spin polarization was not adopted in this study.…”

Section: Computational Detailsmentioning

confidence: 99%

Effects of B on the Segregation Behavior of Mo at the Fe–Cr(111)/Cr2O3(0001) Interface: A First-Principles Study

Zhang

et al. 2020

Metals

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The addition of B can inhibit the precipitation of σ phases at the grain boundary to improve the hot workability and corrosion resistance for super austenitic stainless steel with high Cr and Mo content. This study focused on the interaction between B and Mo at the Fe–Cr(111)/Cr2O3(0001) interface and its effect on interfacial adhesion by employing the first-principles method, especially the effect of B on the segregation behavior of Mo. The most stable O-terminated Fe/Cr2O3 interface was chosen as the basic configuration. The segregation energy and the work of separation were calculated for the metal/chromia interface with Fe–Cr as the substrate. It has been demonstrated that B can promote the diffusion of Mo atoms into the oxide layer to increase the content of Mo in the passive film. In addition, the interfacial adhesion is higher at the most segregated sites. However, it is more difficult for two or more Mo atoms than a single Mo atom to diffuse into the oxide part with the effect of B, indicating that B can only improve the Mo content of the passive film to a small extent. The electronic properties were also further discussed to analyze the interactions and the binding characters between doped atoms and their surrounding atoms and to explain the underlying reasons for the variation of interfacial adhesion.

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Section: Computational Detailsmentioning

confidence: 99%

Effects of B on the Segregation Behavior of Mo at the Fe–Cr(111)/Cr2O3(0001) Interface: A First-Principles Study

Zhang

et al. 2020

Metals

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“…The equations of state and elastic parameters of the present Fe-based alloys and transition metal alloys were calculated using the EMTO method which was used in several former works [9,11,[24][25][26][27][28][29][30][31].…”

Section: Total Energy Calculationsmentioning

confidence: 99%

“…Within the DLM picture, a paramagnetic Fe-Cr-Ni-M quaternary alloy is described as an eight-component (Fe ↑ Fe ↓ ) 0.6−x (Cr ↑ Cr ↓ ) 0.2 (Ni ↑ Ni ↓ ) 0.2 (M ↑ M ↓ ) x alloy with equal amounts of spin up (↑) and spin down (↓) components. Using the DLM scheme, the impact of the loss of the magnetic moment above the Curie temperature on the total energy is properly taken into account, although our calculations were formally still performed at 0 K.The equations of state and elastic parameters of the present Fe-based alloys and transition metal alloys were calculated using the EMTO method which was used in several former works [9,11,[24][25][26][27][28][29][30][31].…”

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confidence: 99%

Elastic Parameters of Paramagnetic Fe–20Cr–20Ni-Based Alloys: A First-Principles Study

Al-Zoubi

2019

Metals

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The single-crystal and polycrystalline elastic parameters of paramagnetic Fe 0.6−x Cr 0.2 Ni 0.2 M x (M = Al, Co, Cu, Mo, Nb, Ti, V, and W; 0 ≤ x ≤ 0.08) alloys in the face-centered cubic (fcc) phase were derived by first-principles electronic structure calculations using the exact muffin-tin orbitals method. The disordered local magnetic moment approach was used to model the paramagnetic phase. The theoretical elastic parameters of the present Fe-Cr-Ni-based random alloys agree with the available experimental data. In general, we found that all alloying elements have a significant effect on the elastic properties of Fe-Cr-Ni alloy, and the most significant effect was found for Co. A correlation between the tetragonal shear elastic constant C and the structural energy difference ∆E between fcc and bcc lattices was demonstrated. For all alloys, small changes in the Poisson's ratio were obtained. We investigated the brittle/ductile transitions formulated by the Pugh ratio. We demonstrate that Al, Cu, Mo, Nb, Ti, V, and W dopants enhance the ductility of the Fe-Cr-Ni system, while Co reduces it. The present theoretical data can be used as a starting point for modeling the mechanical properties of austenitic stainless steels at low temperatures. of the alloying effects on the elastic parameters of paramagnetic fcc Fe-20Cr-20Ni-xM. Specifically, we investigated the changes in the single-crystal and polycrystalline elastic constants caused by adding small concentrations of M (M = Al, Co, Cu, Mo, Nb, V, and W; 0 ≤ x ≤ 8, where x is in atom %) that are soluble in the Fe-Cr-Ni system. We chose these alloying elements since they represent simple metal (Al), as well as nonmagnetic (Cu, Mo, Nb, V, and W) and magnetic (Co) transition metals. We excluded Cr and Ni from this study, since the effects of these alloying elements on the elastic properties of a paramagnetic fcc Fe-Cr-Ni system were discussed previously by Vitos et al. [11].In the present work, all quaternary alloys were treated as substitutional disordered paramagnetic solid solutions with an ideal fcc structure. The paramagnetic phase was modeled using a disordered local moment scheme, which describes the systems well above the magnetic transition temperatures.The rest of the paper includes two sections and conclusions. In Section 2, we describe the ab initio method, the elastic parameters, and the details of the numerical calculations. We present the results and the discussion in Section 3. Methodology Total Energy CalculationsThe calculations in this work are based on density functional theory [12,13] and the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation [14] for the exchange correlation functional. The exact muffin-tin orbitals (EMTO) method [10,[15][16][17][18][19] in combination with the scalar-relativistic scheme and soft-core approximation was used to solve the Kohn-Sham equations. The chemical and magnetic substitutional disorder was treated using coherent potential approximation (CPA) [20,21]. The total energy was computed using full char...

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“…The Bain path is an appropriate model for studying the energetics of the bcc-fcc martensitic transformation. Furthermore, monitoring the alloying induced softening or hardening of Fe-based alloys against tetragonal distortions (Al-Zoubi, Johansson, Nilson, & Vitos, 2011) is of key importance for understanding the interstitial driven martensitic transformations in alloy steels.…”

Section: Bain Pathmentioning

confidence: 99%

Alloy Steel: Properties and Use First-Principles Quantum Mechanical Approach to Stainless Steel Alloys

Al-Zoubi¹,

Lu²,

Kokko³

et al. 2011

Alloy Steel - Properties and Use

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The Bain path of paramagnetic Fe-Cr based alloys

Cited by 19 publications

References 37 publications

Effects of B on the Segregation Behavior of Mo at the Fe–Cr(111)/Cr2O3(0001) Interface: A First-Principles Study

Effects of B on the Segregation Behavior of Mo at the Fe–Cr(111)/Cr2O3(0001) Interface: A First-Principles Study

Elastic Parameters of Paramagnetic Fe–20Cr–20Ni-Based Alloys: A First-Principles Study

Alloy Steel: Properties and Use First-Principles Quantum Mechanical Approach to Stainless Steel Alloys

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