TMAl(TM=Ir、Ru和Os)金属间化合物高压下力学性能的第一性原理研究

Influence of High Pressure on the Mechanical Properties of TMAl(TM=Ir, Ru and Os) from First-Principle Calculations

采用第一性原理方法研究了TMAl (TM=Ir、Ru和Os)三种金属间化合物在高压下晶格常数、弹性常数和弹性模量的变化规律。结果表明,三种金属间化合物的晶格常数和晶胞体积随着压力的增加而减小。通过对TMAl金属间化合物弹性性质的分析,发现它们的弹性系数和弹性模量随着压力的增加几乎呈线性增大。这主要是由于在压力的作用下,体相中TM原子和Al原子的相互作用增强,TM-Al金属键的键长变短所导致的。此外,三种金属间化合物在常压下表现为塑性行为,并随着压力增加而进一步增强。Ir Al的普适弹性各向异性接近于零,表明其具有较好地抵抗微裂纹产生的能力。

By means of first-principle approach,the influences of high pressure on the lattice parameters,elastic constants and elastic modulus of TMAl(TM=Ir,Ru and Os)are investigated.The results show that the calculated lattice parameters and unit-cell volume of TMAl alloys decrease as pressure increases.By analysis of the elastic properties of TMAl alloy,their elastic constants and elastic modulus increase almost linearly with increasing pressure.The main reason is that the high pressure improves the charge interaction between TM atom and Al atom.As a result,the bond length of TM-Al metallic bond becomes shorter.In addition,TMAl alloy exhibits plastic behavior under normal pressure,which is further strengthened with increasing pressure.The universal elastic anisotropy of IrAl is close to zero,indicates that IrAl exhibits a good ability to resist micro-cracks.