双相TiAl基合金γ相中螺旋状普通位错的形成

利用自行开发的精确立体显微术研究了800℃压缩变形2％的双相TiAl基合金γ相中普通位错的空间形态。研究结果表明，同一位错往往并不处于同一晶面，其中一些位错段靠近（111）晶面，另一些则靠近（112）晶面，构成三维螺旋状曲线。普通位错形成这种螺旋状曲绠交滑移的结果，即原先在（111）密排面滑移的螺位错的部分位错段交滑移到（112）非密排面。随着处于不同晶面的位错段的进一步滑移，靠近位错段交界处的位错线方向将发生变化，具有较大刃型分量的部分可通过攀移而偏离（111）或（112）晶面。

Formation of HelicalDislocations in

The stereo morphology of ordinary dislocations in the γ-phase in a Ti-48Al alloy after compressed 2% at 800℃ was studied by developing an accurate stereo microscopy method. It was shown that the segments on one dislocation do not lie on the same plane. Some segments nearly lie on (111) while the others on (112),forming a helix. The dislocation helices might result from the cross slip of some segments on an initial screw dislocation from (111)plane to (112) plane. With the further slipping of the dislocation segments on (111) and (112),the line orientation nearby the nodes of adjacent segments will change,and the segments with larger edge components would deviate from (111) or (112) planes by climbing.