【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.更多还原

【Abstract】 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 behavior at 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 γ_ usf,the stable stacking fault energy γ_ sf,and the unstable twinning fault energy γ_ utf,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)〈011〉{111}.更多还原