γ-TiAl金属间化合物面缺陷能的分子动力学研究  

Molecular dynamics study of deformation mechanism of γ-TiAl intermetallics

作　　者：周宗荣[1] 王宇[1] 夏源明[1] 

机构地区：[1]中国科学技术大学力学和机械工程系中国科学技术大学中科院材料力学行为和设计重点实验室,合肥230027

出　　处：《物理学报》2007年第3期1526-1531,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:90505002)资助的课题.~~

摘　　要：运用分子动力学方法,对γ_TiAl金属间化合物的面缺陷能(层错能和孪晶能)进行了研究.计算得到γ_TiAl不同滑移系(或孪生系)的整体堆垛层错能曲线,结果表明,γ_TiAl较一般fcc晶体结构的金属可动滑移系(孪生系)的数量减少,在外界条件下呈脆性.研究孪生系(1/6)〈112〉{111}的弛豫的整体堆垛层错(GSF)能和整体孪晶(GTF)能曲线,对不稳定层错能γusf、稳定层错能γsf和不稳定孪晶能γusf值进行分析,可以预知,γ_TiAl的主要变形机理为孪生系(1/6)〈112〉{111}的孪生和普通滑移系(1/6)〈110〉{111}的滑移,以及超滑移系(1/2)〈011〉{111}的滑移.The generalized planar fault （GPF） energies of various slip systems in γ-TiAl intermetallics are studied by using molecular dynamics （MD） method. The unrelaxed and relaxed GPF curves of various slip systems are compared. It was show that the γ- TiAl has fewer mobile slip systems than the fcc crystal. It is also found that the γ-TiAl intermetallics would exhibit brittle behaviorat ambient temperature. The relaxed generalized stacking and twinning fault energy curves of （1/6）（112^-） { 111} twinning system are obtained. By analyzing the unstable stacking fault energy γusf, the stable stacking fault energy γaf, and the unstable twinning fault energy γuef, it can be predicted that the major deformation mechanisms are twinning （1/6）（112）{ 111} and ordinary dislocation slip （1/2） 〈 110〉 { 111 }, as well as superdislocation slip （1/2） 〈01^-1 〉 { 111 }.

关 键 词：Γ-TIAL 堆垛层错能 孪晶能 分子动力学 

分 类 号：O482[理学—固体物理]