第一性原理研究压力对Fe2B的结构、机械性质的影响

基于密度泛函理论的第一性原理方法，系统研究了0～30 GPa压力下四方相Fe₂B的结构，稳定性和力学性质等.随着压力的增加，计算得到的晶格参数逐渐减小，所有结构均满足热力学稳定性，体积模量和剪切模量逐渐增大，韧性得到有效改善.硬度呈现先增大后减小的趋势，并在18 GPa压力时达到最大值，各向异性先增大后减小.德拜温度变化趋势与杨氏模量的变化趋势相同.同时还研究了相变结构——正交相的相关性质，结果表明其结构满足热力学稳定性但不满足力学稳定性，是否稳定存在还需要进行后续实验研究.

First-principles study on the effect of pressure on the structure and mechanical properties of Fe2B

Based on the first-principles method of density functional theory, the structure, stability and mechanical properties of tetragonal Fe2B under pressures of 0~30GPa were systematically studied. The results show that with the increase of pressure, the calculated lattice parameters gradually decrease, all structures satisfy the thermodynamic stability, the bulk modulus and shear modulus increase gradually, and the toughness is effectively improved. The hardness first increases and then decreases, and reaches the maximum value at 18GPa pressure. The anisotropy increases first and then decreases. The changing trend of Debye temperature is the same as that of Young''s modulus. At the same time, the related properties of the phase transition structure—orthorhombic phase were also studied. The results show that its structure satisfies the thermodynamic stability but does not satisfy the mechanical stability, so, whether it is stable or not still needs to be studied by subsequent experiments.