P合金化浓度对NiAl力学性能影响的第一原理计算

First-Principles Calculations for Influence of P Alloying Concentration on the NiAl Alloy's Mechanical Properties

采用第一原理赝势平面波方法,基于虚拟晶体势函数(VCA)近似,计算分析了P元素合金化浓度(浓度x≤6.25%)的变化对NiAl合金力学性能的影响。通过对弹性模量的计算分析,发现P合金化浓度在0.125%(原子百分比)附近,B2-NiAl晶体的延性最好、硬度最小,在0.188%附近,B2-NiAl晶体产生强烈的固溶强化硬度急剧增大,但延性下降,在1.25%附近及在3.75%～6.25%区间,B2-NiAl晶体的延性有所改善,但在0.5%附近,B2-NiAl晶体的延性最差。

The first-principles plane-wave pseudopotential method based on virtual crystal approximation(VCA) was used to calculate and analyze P alloying elements concentration(x concentrations below 6.25%) changes and its influence on the NiAl alloy's mechanical properties.Based on the calculation of B2-NiAl elastic modulus,results show that at the P alloy concentration of x=0.125%(both atomic percent) the B2-NiAl crystal has the best ductility,and minimum hardness.Around x=0.188% B2-NiAl crystal produces strong solid solution strengthening and the hardness increases rapidly,but the ductility drops.Around x=1.25% and x=3.75%～6.25% interval,B2-NiAl crystal's ductility improves.Around x=0.5% B2-NiAl crystal's ductility is the worst.