第一性原理计算Si和Ga掺杂对BCC-Fe广义层错能的影响  

Effect of Si and Ga doping on generalized stacking fault energy of BCC-Fe using first-principle calculations

作　　者：陈溥芃 王洋[1] 张元祥[1] 方烽 张晓明[1] CHEN Pupeng;WANG Yang;ZHANG Yuanxiang;FANG Feng;ZHANG Xiaoming(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《钢铁研究学报》2023年第3期347-354,共8页Journal of Iron and Steel Research

基　　金：国家自然科学基金青年基金资助项目(52104372);中央高校基本科研业务费资助项目(N2107001);国家博士后科学基金面上资助项目(2019M651129)。

摘　　要：采用第一性原理计算了BCC-Fe以及BCC-Fe分别掺杂硅(Si)、镓(Ga)后{112}<111>滑移系的广义层错能。结果表明:Si和Ga均会降低BCC-Fe的广义层错能,对广义层错能曲线峰值的降低幅度分别为8.48%和10.27%;不同元素掺杂也会影响层错发生的位置,Si掺杂的BCC-Fe趋向于在Si原子所在的{112}面发生<111>方向的层错,而Ga掺杂的BCC-Fe更趋向于在与Ga原子近邻的{112}面发生<111>方向的层错。此外,BCC-Fe上下层沿着{112}<111>滑移系错动2/3b_(p)(b_(p)=1/2<111>)时,会形成薄层孪晶结构,使2/3b_(p)处的广义层错能显著降低。与错动1b_(p)后形成的完美晶体相比,薄层孪晶为亚稳定状态,可通过相邻的{112}平行晶面逐层错动2/3b_(p),从而生成多层孪晶来进一步降低层错能,一定程度上解释了Fe-Si、Fe-Ga合金中发现大量∑3孪晶界的现象。The generalized stacking fault energy of the{112}<111>slip system of BCC-Fe and BCC-Fe doped with Si and Ga were calculated by first-principles,respectively.The results show that both Si and Ga can reduce the generalized stacking fault energy of BCC-Fe,and the reductions to the peak value of the generalized stacking fault energy curve are 8.48%and 10.27%,respectively.Doping of different elements also affects the location of stacking faults.The Si-doped BCC-Fe tends to generate stacking faults at the{112}plane where Si atom is located,while the Ga-doped BCC-Fe is more prone to generate stacking faults at the{112}plane adjacent to Ga atom.In addition,a thin-layer twin will be formed when the lower half of the BCC-Fe relative to the upper half sliping a displacement of 2/3b_(p)along the<111>direction,which significantly reduces the generalized stacking fault energy of 2/3b_(p).Compared with the perfect crystal formed by the displacement of 1b_(p),the thin-layer twin is a metastable state.In order to further reduce the generalized stacking fault energy,a series of adjacent{112}parallel planes can slip along the<111>direction by 2/3b_(p)layer by layer,leading the generation of multi-layer twin.This work can explain the phenomenon that a large number of∑3 twin boundaries were found in Fe-Si and Fe-Ga alloys,to some extent.

关 键 词：BCC-Fe {112}<111>滑移系 广义层错能 薄层孪晶 第一性原理 局域电荷密度 

分 类 号：TG113.22[金属学及工艺—物理冶金]