γ—TiAl单晶中(1/2)〈110]位错的行为

THE BEHMAVIORS OF (1/2)〈110] DISLOCATIONS IN γ-TiAl SINGLE CRYSTALS

[021]取向的γ—TiAl单晶（Ti—56％Al,原子分数）在－196－1000℃温度范围内压缩变形时主要形变方式为｛111｝（110］普通位错的滑移低温时，（1／2）（110］普通位错大多沿螺型及60°交角两种方向排列，井倾向于成组出现；而在反常屈服温度区域内，（1／2）（110］普通位错大多平行于其螺型方向，且形成许多位错拐点，其数目随温度的升高而增加；在反常屈服峰温以上，普通位错不具有特殊的方向性。

The main deformation mode for [021]-oriented γ-TiAl single crystals in thetemperature range of -196 -1000 ℃ has been identified to be {111}(110] ordinary dislocationslip. At low temperatures, (1/2)(110] ordinary dislocations are mostly parallel to their screworientation or 60° with respect to screw orientation and tend to be arranged in groups. Whilein the anomalous yield temperature range, (1/2)(110] ordinary dislocations are mostly parallelto their screw orientation and are heavily cusped. The number of these cusps increases withincreasing temperature. Above the peak temperature, ordinary dislocations do not exhibit allypreferable orientation and tend to move out of their primary slip plane by climbing.