A theoretical investigation on the effect of anti-site point defects on mechanical and thermodynamic properties of MgZn₂ and MgCu₂ based on the first-principles calculations has been implemented. The results show that Mg anti-site defect on Zn or Cu site plays a reinforcing role, while exhibiting a more brittle behavior. However, the defect phase of Cu anti-sites on Mg sublattice shows a ductile tendency. The temperature-dependent thermodynamic properties are also predicted along with Debye-Grüneisen model including Debye temperature, thermal expansion coefficient and vibrational heat capacity as well as vibrational entropy. Taking into account the contribution of the lattice vibration and thermal electronic excitations, the Helmholtz free energy F can be calculated, suggests that anti-site defects caused by the occupancy of Mg at the Zn or Cu site are thermodynamically unstable compared to the defect-free phases. In addition, the total amount of charge transfer, the overall and the local difference charge densities are further discussed to analyze the mechanism of mechanical properties.

基于第一性原理计算，对反点缺陷对MgZn ₂和MgCu ₂的力学和热力学性质的影响进行了理论研究。结果表明，Mg在Zn或Cu位上的抗位缺陷起着增强作用，同时表现出更脆的行为。然而，Mg亚晶格上Cu反位的缺陷相表现出延展性。与温度有关的热力学性质也会与Debye-Grüneisen模型一起预测，包括Debye温度，热膨胀系数和振动热容以及振动熵。考虑到晶格振动和热电子激发的贡献，亥姆霍兹自由能F可以计算得出，与无缺陷相相比，由Mg在Zn或Cu位置处引起的反位缺陷在热力学上是不稳定的。此外，进一步讨论了电荷转移的总量，总电荷电荷密度和局部电荷密度差异，以分析机械性能的机理。