奥氏体316不锈钢微观缺陷的热演化

Thermal Evolution of Micro-defects in Type-316 Austenitic Stainless Steel

从微观结构缺陷热演化的角度研究奥氏体316不锈钢。对样品由373 K升温到1473 K,然后间隔50 K,等时退火。微观缺陷由正电子湮没谱(positron annihilation spectroscopy,PAS)和透射电子显微镜(transmission electron microscope,TEM)表征。随着退火温度的升高,空位型缺陷逐渐回复。在退火温度673~823 K范围内,出现明显的位错聚集和位错网的非均匀分布。在退火温度873 K后,位错型缺陷逐渐回复。退火温度873~973 K时有大型微观析出相析出。随后,析出相尺寸减小,大部分在1123 K之前回溶。在1373 K退火后,样品中几乎没有缺陷。

Thermal evolution of micro-defects and micro-hardness in type-316 austenitic stainless steel was investigated using positron annihilation spectroscopy(PAS)and transmission electron microscope(TEM).The results revealed that the vacancy defects gradually recovered with the increase of annealing temperature.In annealing temperature range of 673 K to 823 K,obvious dislocation aggregation and non-uniform distribution of dislocation network appeared.After annealing at 873 K,dislocation defects gradually recovered.When the annealing temperature was from 873 K to 973 K,there were large micro-precipitates in the steel.Subsequently,the precipitates became smaller;and most of them were dissolved before 1123 K.After annealing at 1373 K,it exited no defects basically in the specimen.