Using a combination of first-principles calculations, special quasi-random structures and quasi-harmonic Debye model methods, we investigated the structural properties, magnetic moments, phase stability, electronic structure, mechanical properties and thermodynamic properties of fcc and bcc FeNi_1-xCr_x disordered alloys. The results show that the volume per atom and lattice constant of fcc and bcc FeNi_1-xCr_x alloys exhibit different nonlinear decreasing trends with increasing Cr content, which can be understood by the coupling effect of the composition-dependent antiferromagnetic interaction and atomic volume. Only fcc FeNi_1-xCr_x alloys with x less than 0.25 are relatively easy to synthesize, while FeNi_1-xCr_x alloys with other compositions all have a strong tendency to phase separation. The DOS of fcc and bcc FeNi_1-xCr_x alloys gradually moves to the shallower energy level with the increase of Cr content, which makes TDOS narrow. As the Cr content increases, the hardness and rigidity of fcc FeNi_1-xCr_x (x = 0, 0.125, and 0.25) alloys gradually increase, while the toughness, ductility and compression resistance gradually weaken. Increasing Cr content is beneficial to reduce the volumetric thermal expansion coefficient of fcc FeNi_1-xCr_x (x = 0, 0.125, and 0.25) alloys, which also can decrease Debye temperature and weaken interaction between atoms.

通过结合第一性原理计算，特殊的准随机结构和准谐波Debye模型方法，我们研究了fcc和bcc FeNi _1-x的结构性质，磁矩，相稳定性，电子结构，机械性质和热力学性质。Cr _x无序合金。结果表明，fcc和bcc FeNi _1-x Cr _x合金的每原子体积和晶格常数随Cr含量的增加呈现出不同的非线性下降趋势，这可以通过成分相关的反铁磁相互作用与原子体积的耦合效应来理解。仅fcc FeNi _1-x Cr _xx小于0.25的合金相对容易合成，而其他成分的FeNi _1-x Cr _x合金都具有很强的相分离趋势。随着Cr含量的增加，fcc和bcc FeNi _1-x Cr _x合金的DOS逐渐移至较浅的能级，这使TDOS变窄。随着Cr含量的增加，fcc FeNi _1-x Cr _x（x = 0、0.125和0.25）合金的硬度和刚度逐渐增加，而韧性，延展性和抗压缩性则逐渐减弱。Cr含量的增加有利于降低fcc FeNi _1-x Cr _x的体积热膨胀系数 （x = 0、0.125和0.25）合金，也可以降低德拜温度并削弱原子之间的相互作用。