中文摘要：

采用第一性原理方法研究了微量B元素对Pt3Al合金的结构稳定性和力恘性能的影响，详细讨论了四面体间隙位置和八面体间隙位置两种添加方式。计算了它们的晶格参数、弹性常数、弹性模量和电子结构等性质。计算结果表明，微量B元素引起Pt3Al合金的晶格膨胀。同时，B在四面体位置比八面体位置要稳定存在。弹性模量的计算表明，B 在四面体位置削弱了Pt3Al合金的抗体积变形能力、抗剪切变形能力和弹性硬度。通过电子结构计算表明，微量B元素在Pt3Al合金中形成了Pt-B键和Al-B键，削弱了Pt-Al金属键的键结合能力。

英文摘要：

The effect of B element on structural stability and mechanical properties of Pt3Al alloy was investigated by using first-principles calculations.Two different B doping such as tetrahedral interstice （TI） and octahedral interstice （OI） were considered in detail. The lattice parameters, elastic constants, elastic modulus and electronic structure were calculated. The calculated results have shown that the doped B results in lattice expansion for Pt3Al alloy, and the TI site is more stable than that of OI site. The calculated elastic modulus indicated that the doped B weakens the volume and shear deformation resistances and reduces the elastic stiffness. The calculated electronic structure has shown that Pt-B and Al-B bonds were formed in Pt3Al alloy and weaken the bond strength of Pt-Al metallic bond.