Elastic properties of 4d transition metal alloys: Values and trends

Al-Zoubi, Noura; Schönecker, Stephan; Li, Xiaoqing; Li, Wei; Johansson, Börje; Vitos, Levente

doi:10.1016/j.commatsci.2018.12.027

Cited by 14 publications

(7 citation statements)

References 51 publications

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“…The scaling between C fcc (C bcc ) and ∆E for Fe-Cr-Ni-based alloys holds. Our observations on the correlation between C and ∆E are in line with those obtained by [39][40][41][42][43][44].…”

Section: Polycrystalline Elastic Constantssupporting

confidence: 91%

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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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Section: Polycrystalline Elastic Constantssupporting

confidence: 91%

“…The cubic shear elastic constants C and C 44 were computed by keeping the volume constant during deformations of the conventional cubic cell. For the tetragonal shear modulus C , the following orthorhombic deformation was used:…”

Section: Introductionmentioning

confidence: 99%

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

Al-Zoubi

2019

Metals

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“…The above finding suggests that the remaining residuals of the linear regression model can be reduced if the model includes some other descriptors of the electronic bands in addition to Δdip and x sp . As indicated in the recent DFT calculations, the energetic properties of the transition metal alloys could connect closely with many band features, including the transition between e g and t 2g orbital sets 25 , e g / t 2g population ratio 17 , band occupation fraction 14,22,23 , and upper band edge 26 . Therefore, we propose an additional regression function, which is added on the basis of Eq.…”

Section: Resultsmentioning

confidence: 74%

“…Electronic structures related to defect–solute interactions can be potential candidates for such descriptors, which have been suggested by many recent first-principles calculations. Some of these studies were related to electronic band filling effects 14,22,23 ; others also indicated alternative electronic structure features that can affect energetic properties of the transition metal alloys, including d- band bimodality 24 , the transition between e g and t 2g orbital sets 25 , e g / t 2g population ratio 17 , and upper band edge 26 .…”

Section: Introductionmentioning

confidence: 99%

Local electronic descriptors for solute-defect interactions in bcc refractory metals

Zhao

Zhang

et al. 2019

Nat Commun

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The interactions between solute atoms and crystalline defects such as vacancies, dislocations, and grain boundaries are essential in determining alloy properties. Here we present a general linear correlation between two descriptors of local electronic structures and the solute-defect interaction energies in binary alloys of body-centered-cubic (bcc) refractory metals (such as W and Ta) with transition-metal substitutional solutes. One electronic descriptor is the bimodality of the d-orbital local density of states for a matrix atom at the substitutional site, and the other is related to the hybridization strength between the valance sp- and d-bands for the same matrix atom. For a particular pair of solute-matrix elements, this linear correlation is valid independent of types of defects and the locations of substitutional sites. These results provide the possibility to apply local electronic descriptors for quantitative and efficient predictions on the solute-defect interactions and defect properties in alloys.

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“…In the following, we further discuss the correlations of these results with the filling fraction of the valence d orbitals in Fig. 5, as the d-band filling effect is generally essential in determining physical and mechanical properties of the transition metal elements and their alloys [28,39,63,64].…”

Section: Dft Results On γ Usf and γ Surfmentioning

confidence: 99%

Screening of generalized stacking fault energies, surface energies and intrinsic ductile potency of refractory multicomponent alloys

Sundar

Ogata

et al. 2020

Preprint

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Body-centered cubic (bcc) refractory multicomponent alloys are of great interest due to their remarkable strength at high temperatures. Meanwhile, further optimizing the chemical compositions of these alloys to achieve a combination of high strength and room-temperature ductility remains challenging, which would require systematic predictions of the correlated alloy properties across a vast compositional space. In the present work, we performed first-principles calculations with the special quasi-random structure (SQS) method to predict the unstable stacking fault energy (γ usf ) of the (1 10) [111] slip system and the (1 10)-plane surface energy (γ surf ) for 106 individual binary, ternary and quaternary bcc solid-solution alloys with constituent elements among Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re and Ru. Moreover, with the first-principles data and a set of physics-informed descriptors, we developed surrogate models based on statistical regression to accurately and efficiently predict γ usf and γ surf for refractory multicomponent alloys in the 10-element compositional space. Building upon binary and ternary data, the surrogate models show outstanding predictive ability in the high-order multicomponent systems. The ratio between γ surf and γ usf is a parameter to reflect the potency of intrinsic ductility of an alloy based on the Rice model of crack-tip deformation. Therefore, using the surrogate models, we performed a systematic screening of γ usf , γ surf and their ratio over 112,378 alloy compositions to search for alloy candidates that may have enhanced strength-ductile synergies. Search results were also confirmed by additional first-principles calculations.

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Elastic properties of 4d transition metal alloys: Values and trends

Cited by 14 publications

References 51 publications

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

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

Local electronic descriptors for solute-defect interactions in bcc refractory metals

Screening of generalized stacking fault energies, surface energies and intrinsic ductile potency of refractory multicomponent alloys

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