分子动力学模拟研究单个刃型位错对NiAl马氏体相变的影响  

MOLECULAR DYNAMICS STUDY ON THE INFLUENCE OF SINGLE EDGE DISLOCATION ON MARTENSITIC TRANSFORMATIONS IN NiAl

作　　者：沙宪伟[1] 张修睦[1] 李斌[1] 李依依 

机构地区：[1]中国科学院金属研究所,沈阳110015

出　　处：《金属学报》1997年第11期1121-1129,共9页Acta Metallurgica Sinica

基　　金：国家自然科学基金!59271019

摘　　要：利用嵌入原子类型的势函数，通过分子动力学模拟方法研究了单个刃型位错对NiAl热诱发和应力诱发马氏体相变的影响，不受外力时，单个刃型位错的应变区不能诱发马氏体形核；位错在马氏体的长大过程中被继承，并可在相变的驱动下逐渐运动拉应力作用下，3R结构的应力诱发马氏体首先在位错芯附近形核，长大过程中先形成蝶状马氏体，随后位错多余半原子面的中部也发生了马氏体形核.刃型位错降低了应力诱发马氏体形核的激活能，并在相变中起到了塑性协调作用.Via embedded atom type potential, molecular dynamics simulation has been performed to study the influence of single edge dislocation on both thermally and stress induced martensitic transformations in a stoichiometric NiAl B2 alloy. If no external force is applied to the system, the strain field of single edge dislocation can not nucleate martensites. Edge dislocation can be inherited during the growth processes of thermally induced martensite, and can also migrate toward the surface with the help of the transformation. When a tensile force is applied, stress induced martensite with 3R structure can initially nucleate near the dislocation core. Butterfly martensite appeared first during the growth process, and then another martensitic variant nucleated in the middle of the dislocation.Edge dislocation can reduce the activation energy for stress induced martensitic nucleation, and it also plays a role of plastic accommodation in the transformation processes.

关 键 词：马氏体相变 刃型位错 分子动力学 模拟 镍铝 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TG113.12[金属学及工艺—金属材料]