We have applied the first-principles method to predict the phase stability, elastic and thermodynamic properties of ternary (AlCrFe, AlCrNi, CrFeNi and AlFeNi) and quaternary (AlCrFeNi) medium-entropy alloys (MEAs). Both body-centered cubic (BCC) and face-centered cubic (FCC) disordered structures are described using the special quasi-random structures (SQSs) technique. AlCrFe, AlCrNi and AlCrFeNi are favorable in single BCC structures, while CrFeNi is likely to form a single FCC structure. Addition of Ni help stabilizes AlCrFeNi quaternary MEAs. Al and Cr addition are in favor of the formation of BCC AlCrFeNi. Addition of Al, Cr and Ni reduce the resistance to volume deformation for quaternary AlCrFeNi due to the effect of the average number of [Formula: see text]-electrons. The ternary MEAs have better resistance to shear deformation and elastic stiffness than quaternary AlCrFeNi. In addition, all the considered MEAs embody elastic anisotropy and AlCrFeNi are predicted to be ductile behavior. Finally, volumetric thermal expansion coefficient, constant volume heat capacity, vibrational and electronic entropy, and Helmholtz free energies of stable BCC AlCrFeNi, BCC AlCrFe, BCC AlCrNi and FCC CrFeNi are calculated using the Debye–Grüneisen model in temperature ranging from 0 to 1200 K to elucidate the relationships between thermodynamic parameters and temperature.

中文翻译：

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AlCrFeNi中熵合金相稳定性、弹性和热力学性能的第一性原理研究

我们应用第一性原理方法来预测三元（AlCrFe、AlCrNi、CrFeNi 和 AlFeNi）和四元（AlCrFeNi）中熵合金（MEA）的相稳定性、弹性和热力学性质。使用特殊的准随机结构 (SQS) 技术描述了体心立方 (BCC) 和面心立方 (FCC) 无序结构。AlCrFe、AlCrNi 和 AlCrFeNi 有利于形成单一的 BCC 结构，而 CrFeNi 很可能形成单一的 FCC 结构。Ni的添加有助于稳定AlCrFeNi四元MEA。Al和Cr的添加有利于BCC AlCrFeNi的形成。由于[公式：见正文]-电子平均数的影响，添加 Al、Cr 和 Ni 会降低四元 AlCrFeNi 的体积变形阻力。三元MEA比四元AlCrFeNi具有更好的抗剪切变形和弹性刚度。此外，所有考虑的 MEA 都体现了弹性各向异性，并且预测 AlCrFeNi 具有延展性。最后，使用 Debye-Grüneisen 模型在 0 到 1200 K 温度范围内计算了稳定的 BCC AlCrFeNi、BCC AlCrFe、BCC AlCrNi 和 FCC CrFeNi 的体积热膨胀系数、恒定体积热容、振动和电子熵以及亥姆霍兹自由能阐明热力学参数与温度之间的关系。