Transition-metal-element dependence of ideal shear strength and elastic behaviors of γ′-Ni3Al: ab initio study to guide rational alloy design
| Autor: | Minru Wen, Yifan Gao, Zhongfei Mu, Xing Xie, Chong-Yu Wang, Fugen Wu, Huafeng Dong |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Mechanical Engineering Alloy Metals and Alloys Ab initio Thermodynamics Stiffness 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Superalloy Shear (geology) Mechanics of Materials Materials Chemistry medicine engineering Density functional theory medicine.symptom 0210 nano-technology Elastic modulus Monoclinic crystal system |
| Zdroj: | Journal of Alloys and Compounds. 806:1260-1266 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2019.07.284 |
| Popis: | When doped with transition-metal (TM) elements, modern commercial Ni-based superalloys achieve an extraordinary mechanical performance, including elastic behaviors and shear strength. By using density functional theory, the TM-element (3d:Sc–Zn, 4d:Y–Cd, 5d:Hf–Au) dependence of the elastic properties and the ideal shear strength of γ′-Ni3Al were determined. According to the positive definiteness requirement of the elastic stiffness coefficients matrix, we present the necessary and sufficient mechanical stability in terms of Born criteria for a monoclinic crystal system. By examining the mechanical stability and calculating the stress–strain curve at every single strain, the shear behavior of pure Ni3Al in the weakest shear-slip system was investigated in detail. Our results show that the d-orbital occupancy of TM elements can affect the mechanical properties of the γ′ phase significantly when they occupy the Al site in Ni3Al, where the elements toward the center part of each series (e.g. V, Cr, Mn, Nb, Mo, Ru, Ta, W, Re, and Os) can enhance the elastic constants, elastic moduli, and shear strength. Elements at the beginnings and ends of the series (such as Cu, Zn, Y, Ag, Cd, and Au) will decrease the elastic properties and shear strength of γ′-Ni3Al. |
| Databáze: | OpenAIRE |
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