奥氏体不锈钢的回复与再结晶机制

Recovery and recrystallization mechanism in austenitic stainless steel

研究了奥氏体不锈钢经等通道转角挤压冷变形后在退火过程中的组织变化。具有低层错能的奥氏体不锈钢在退火过程中可以发生多边化过程;亚晶的形成与长大方式有:a)形变带→带内位错胞→亚晶;b)形变带→高密度位错形变带界面→多边化→位错墙→亚晶。亚晶以晶界凸出机制迁移生长以及合并机制生长。再结晶的形核与生长:亚晶的不断长大形成再结晶晶核,晶核以凸出机制迁移长大。凸出机制在微观上是台阶长大机制,合并机制从宏观上看是晶粒转动机制。这两种机制是亚晶长大与再结晶晶核生长的基本机制。

The microstructure of ECAPed 304L austenitic stainless steel during annealing was studied experimentally.The results show that polygonization occurs for the austenitic stainless steel with low stacking fault energy during annealing.The process of formation and growth for sub-grain is as follows：（a） deforming bands → dislocations cells within bands→ sub-grains;（b） deforming bands →boundaries of deforming bands with high dense dislocations →polygonization →dislocation walls→sub-grains.Sub-grains grew through the mechanisms of grain boundary bulge and merging of sub-grains.The recrystallization is the process of grain nucleation through the continuous growth of sub-grains and growth of grains by the mechanisms grain boundary bulge.The mechanism of grain boundary bulge is a step-growth process and the merging of sub-grains is the mechanisms of grain rotation.Both of the mechanisms are the basic mechanisms during recovery and recrystallization.