形变孪晶的消失与退火孪晶的形成机制

Annihilation of Deformation Twins and Formation of Annealing Twins

等径角挤压变形奥氏体不锈钢的退火研究表明,层错与形变孪晶是在回复阶段开始退化与消失的,层错的退化与消失主要是由于相邻亚晶以及内部形成的新亚晶以凸出机制逐渐吞并层错的结果。孪晶的退化与消失包括两个方面原因:相邻亚晶以凸出机制逐渐吞并形变孪晶;孪晶板条以合并机制逐渐减少板条数量而使板条扩宽,最终宽板条的孪晶界面由于位错的运动而消失。退火孪晶形成于回复阶段,是大角度界面的迁移结果。

The investigation on ECAPed austenitic stainless steel during annealing shows that annihilation of stacking faults and deformation twins could occur during the recovery process due to being swallowed up gradually by adjacent sub-grains and new formed sub-grains within the area of stacking faults in the form of bulge mechanism. Annihilation of deformation twins included two aspects of reason; deformation twins were swallowed up gradually by adjacent sub-grains in the form of bulge mechanism; the number of lamellae decreased and the width of twin lamellae increased gradually in the form of consolidation mechanism, eventually the interfaces of twins with widened lamellae disappeared due to the dislocation activity. The formation of annealing twins was the result of migration of high angle boundary during the recovery.