Ir-Rh合金力学性能的第一性原理计算

采用基于密度泛函理论的第一性原理分析方法，用虚拟晶格近似方法计算了Ir-x Rh (x=0、1、2、3、4、5、6、7、8、9、10、12、15、17、20、22、25、27、30)合金的晶格参数、体积模量、剪切模量、杨氏模量等力学参数。通过计算焓变值、电子态密度、能带结构从电子角度分析Rh掺杂对Ir-Rh合金力学性能的影响。结果表明：在Ir中掺杂少量Rh，能够提高材料的强度和硬度，在Ir-5Rh处达到顶点，之后随着Rh含量增加略有下降后继续升高，在Ir-10Rh处达到最大值，且数值与Ir-5Rh基本一致；随着Rh含量的增加，焓变值的绝对值由0.186 eV逐渐增加到0.634 eV,Ir-Rh合金热力学稳定性提高。另外，Ir-Rh合金的态密度、能带结构结果表明随着Rh含量的增加，键能升高，Ir-Rh合金脆性逐渐增大。

First-principles calculation of mechanical properties of Ir-Rh alloy

The lattice parameters, bulk modulus, shear modulus, Young''s modulus and other mechanical constants of Ir-xRh (x=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 17, 20, 22, 25, 27, 30) alloys were calculated by using the first-principles analysis method based on density functional theory. The calculation model is established by the virtual crystal potential function approximation method. The effect of Rh doping on the mechanical properties of Ir-Rh alloy was also analyzed from the electronic point of view by calculating the enthalpy change value, electron density of state and energy band structure. The results show that the strength and hardness of the material can be improved by doping a small amount of Rh in Ir. The peak point at Ir-5Rh decreases slightly and then continues to rise, reaching the maximum at Ir-10Rh, and the value is basically the same as that of Ir-5Rh. With the increase of Rh content, the absolute value of enthalpy changed gradually increased from 0.186 eV to 0.634 eV, and the thermodynamic stability of Ir-Rh alloy was improved. In addition, the density of states and band structure of Ir-Rh alloy show that the bond energy increases with the increase of Rh content, and the brittleness of Ir-Rh alloy increases gradually.