NiAl位错核心结构的模拟

来源期刊：中南大学学报(自然科学版)1999年第1期

论文作者：刘震云 林栋梁 黄伯云 曲选辉

文章页码：55 - 58

关键词：NiAl;位错核心结构;计算机模拟;点缺陷

Key words：NiAl; dislocation core structure; computer simulation; point defects

摘    要：利用EAM势函数对NiAl中 <100>,<110>刃位错和<100>螺位错的位错核心结构及<100>刃位错与点缺陷的交互作用进行了模拟研究.结果表明：<100>刃位错在 (001)面沿[110]和[110]方向扩展,呈“蝶形”结构；而<100>刃位错在{110}滑移面上位错核心结构更为紧凑,位错扩展现象不明显.这 和试验中观察到的NiAl中位错进行<100>{110}滑移,而非<100>{001}滑移的结果相一致.<110>位错在(001)面沿[110]和 [110]方向也有所扩展,但同<001>位错相比,沿[110]方向位错核心扩展的宽度更大,由位错应力场导致的原子位移也更明显.通过模拟还发现 <100>螺位错、<100>刃位错、<110>刃位错在滑移面内均无位错的分解现象.<100>刃位错和点缺陷的交互作用模拟结果表明：在位错核心附近引入点缺陷列对位错核心结构的轮廓影响不明显,说明难以通过引入点缺陷,局部改变有序度的方法来影响位错核心结构.

Abstract: Using Embeded Atom Method and static′s relaxation method, the core structure of <100>,<110> edge dislocations, <100> screw dislocation, the interaction between point defects and <100> edge dislocation in NiAl intermetallics were investigated. The results show that <100> edge dislocation expands along and orientation on the (001) slip plane. The core structure of <100> edge dislocaton on (001) plane is like a “butterfly”, while it is much compacter when it lies on {110} slip plane. So NiAl will prefer having a <100>{110} slip system to having <100>{100} slip system as is found in experiments <110> edge dislocation has a more expended core structure and the atoms of dislocation core distort more heavily. No dislocation splitting was found in the studied dislocations. The outlines of dislocation core structures changed very little after a row of point defects are introduced in them which can be explained by point defects′ little effects on the stress field around dislocation core. The results also show that it is hard to change dislocation core structure by decreasing alloy order in the method of introducing limited point defects into the alloy.