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First-principles study on the mechanical and thermodynamic properties of MoNbTaTiW
International Journal of Minerals, Metallurgy and Materials ( IF 4.8 ) Pub Date : 2020-08-27 , DOI: 10.1007/s12613-020-2077-1
Uttam Bhandari , Congyan Zhang , Shengmin Guo , Shizhong Yang

Refractory high-entropy alloys (RHEAs) are emerging as new materials for high temperature structural applications because of their stable mechanical and thermal properties at temperatures higher than 2273 K. In this study, the mechanical properties of MoNbTaTiW RHEA are examined by applying calculations based on first-principles density functional theory (DFT) and using a large unit cell with 100 randomized atoms. The phase calculation of MoNbTaTiW with CALPHAD method shows the existence of a stable body-centered cubic structure at a high temperature and a hexagonal closely packed phase at a low temperature. The predicted phase, shear modulus, Young’s modulus, Poisson’s ratio, and hardness values are consistent with available experimental results. The linear thermal expansion coefficient, vibrational entropy, and vibrational heat capacity of MoNbTaTiW RHEA are investigated in accordance with Debye-Grüneisen theory. These results may provide a basis for future research related to the application of RHEAs.



中文翻译:

MoNbTaTiW的力学和热力学性质的第一性原理研究

耐火高熵合金(RHEAs)在高温下高于2273 K时具有稳定的机械和热性能,因此正在成为高温结构应用的新材料。在本研究中,通过应用基于第一原理密度泛函理论(DFT),并使用具有100个随机原子的大晶胞。用CALPHAD方法对MoNbTaTiW进行的相计算表明,在高温下存在稳定的体心立方结构,在低温下存在六方密堆积相。预测的相,剪切模量,杨氏模量,泊松比和硬度值与可用的实验结果一致。线性热膨胀系数,振动熵,根据Debye-Grüneisen理论研究了MoNbTaTiW RHEA的振动热容量。这些结果可能为与RHEA的应用相关的未来研究提供基础。

更新日期:2020-08-28
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