MX(M=Fe,Ru,Co和Rh, X= Si和Ge) 合金化合物的热力学性质和硬度的第一性原理计算

基于第一性原理,利用赝势平面波法分析MX型合金化合物的结构性质、弹性性质和力学稳定性。计算得到的MSi/Ge的结构参数和形成焓与实验结果以及其他理论计算结果相吻合,结果表明MSi/Ge具有热力学稳定性且易于合成。计算得到了MX型合金化合物的弹性常数、体积模量、剪切模量、杨氏模量、弹性各向同性指标以及泊松比。基于弹性常数,得到了CoSi/Ge和RhSi/Ge的德拜温度-压强曲线。基于计算硬度的半经验模型，计算了该系列物质的硬度。其中，RhSi、FeGe和CoGe具有较高的弹性模量和较低的泊松比，具有成为超硬材料的潜质。

Thermodynamic properties and hardness of MX intermetallics (M=Fe, Ru, Co and Rh, N= Si and Ge) from first principles

Based on the first-principle calculations, the structural properties, elastic properties, mechanical stability, and hardness of MX intermetallics (M=Fe, Ru, Co and Rh, X= Si and Ge) are investigated using the pseudopotential plane-waves method. The obtained structural parameters and formation enthalpies for MSi/Ge systems at 0 GPa are well consistent with experimental and other available theoretical date which indicate that they are thermodynamic stable and can be synthesized easily. Elastic constants, bulk modulus, shear modulus, , Young''s modulus, shear elastic anisotropic factor, and Poisson''s ratio for MX intermetallics are obtained, On the basis of the calculated elastic constants,the pressure-dependent Ddbye temperature of CoSi/Ge and RhSi/Ge systems sre calculated.Furthermore,the hardness of MX intermetallics is calculated using the semiempirical method.In addition,they are potential hard materials because of dthe large hardness,elastic moduli and low Poisson''s ratios.