Fe-Cr-V-Ni-Si-C系多元合金的原子间互作用势的构建及应用

The construction and application of the many-body potential for the Fe-Cr-V-Ni-Si-C system multi-component alloy

使用第一性原理赝势方法及量子化学从头算方法计算的物理量以及最小二乘法拟合的数据构建了多元合金Fe-Cr-V-Ni-Si-C系的原子间互作用势,并利用该原子间互作用势计算了实验合金N5(Fe9.07Cr7.56V0.8Ni0.49Mo0.96Mn1.52Si3.3C),N6(Fe9.65Cr7.72V1.17Ni0.50Mo0.91Mn1.42Si3.3C),N7(Fe9.81Cr7.65V1.58Ni0.46Mo0.86Mn1.35Si3.3C),N8(Fe10.05Cr7.59V2.24Ni0.40Mo0.89Mn1.39Si3.3C)的奥氏体基体能量,研究了合金元素Ni对多元合金奥氏体基体稳定性的影响.计算结果表明,当合金基体中Ni含量从1.02wt%逐渐增加至2.03wt%时,合金N5-N7的奥氏体基体越来越稳定;当合金基体中Ni含量达到2.88wt%时,奥氏体基体稳定性反而下降.研究结果也表明,合金N5-N8基体以奥氏体为主,马氏体为辅.计算结果与X射线衍射实验结果一致.

The interatomie potential function for the Fe-Cr-V-Ni-Si-C system multi-component alloys was constructed by fitting to the data of this alloy system via quantum chemistry ab initio calculation , first-principles pseudopotentials calculation and least squares method. The stability of the austenite matrixs of Fe-Cr-V-Ni-Si-C system alloys was examined by the acquired interatomic potential functions. The effect of Ni element on the stability of the alloy matrix was studied. The results of calculation show that the stability of austenite matrix with nickel content in the range of 1.02-2.03 wt% increases with the increase of nickel content. When the nickel content in the alloys increases to 2.88 wt%, the austenite matrix energy increases and the stability of the austenite matrix decreases accordingly. The austenite matrix energy of N5-N8 alloy is lower than the energy of its martensite phase. Therefore, the microstructure of N5-N8 alloy tends to be of austenite-type. Analysis by XRD indicates that the matrix of N5-N8 alloy is mainly the austenite phase, complemented by martensite. The calculation results agree with the results of XRD.