含氮的Fe-Mn-Si基合金共格界面能的理论计算

Theoretical Calculation of Coherent Interfacial Energy in Nitrogen-Added Fe-Mn-Si Based Alloys

利用改进的离散点阵平面模型(MPLD),引入Smirnov的统计模型,将间隙原子和置换原子对界面能的贡献分开,可计算含有间隙原子的多元合金体系的共格界面能.含N(wN<0.5%)的Fe-Mn-Si基合金{111}fcc//{0001}hcp共格界面能的计算结果表明,N增加合金的共格界面能,间隙原子增加了相界面的结合强度.置换原子对界面能的贡献随温度的上升而增加,而间隙原子的贡献与之相反,两者综合的结果是共格界面能随温度上升而增加.间隙原子C对共格界面能的影响程度大于N,原因是C、N同置换原子的交互作用不同.

Smirnov＇s statistic model was introduced into the modified discrete lattice plane model（MDLP） to separate the contributions from the substitutional and interstitial atoms, so as to deal with the coherent interfacial energy in the multi-component alloys with the addition of interstitial atoms. The calculation resuits of {111}fcc//{0001}hcp interfacial energy in Fe-Mn-Si based alloy with N （ωN〈0. 5%） shows that N increases this kind of energy, as indicates that the interfacial strength can be enhanced due to N addition. And the total interracial energy increases with the increase of temperature, in which the contribution from N or C atom has a negative influencing, compared with that from the substitutional atoms. Because of the different interactions between substitutional （N and C） and interstitial atoms, N has a greater contribution to the interracial energy than C atom.