高温退火过程中316不锈钢晶界特征分布的演化

EVOLUTION OF GRAIN BOUNDARY CHARACTER DISTRIBUTION IN 316 AUSTENITIC STAINLESS STEEL DURING HIGH TEMPERATURE ANNEALING

用扫描电子显微镜(SEM)和电子背散射衍射(EBSD)技术研究了5%冷变形316不锈钢经1100℃不同时间退火样品的晶界特征分布(GBCD)。结果表明:低ΣCSL(Σ≤29)晶界比例的提高是在再结晶过程中实现的。在退火40 min时再结晶完成,低ΣCSL晶界比例达到80%,其中Σ3晶界比例占总的低ΣCSL晶界80%左右,晶界特征分布得到优化;尺寸较大形状不规则的晶粒团簇(grain-clusters)形成,每个晶粒团簇内部存在大量孪晶界、多重孪晶界和特殊的三叉晶界节点。部分再结晶状态样品的显微组织特点和晶粒团簇内部孪晶链的分析表明再结晶过程中多重孪晶的发展是提高316不锈钢低ΣCSL晶界比例的关键。

Grain boundary character distribution of 316 austenitic stainless steel after cold rolled 5% combined with recrystallization annealed at 1100℃ for different times was studied by scanning electron microscope （SEM） and electron backscatter diffraction （EBSD）. The results indicated that the proportion of low-2CSL grain boundaries was enhanced during recrystallization process. The recrystallization finished after annealing for 40 minutes, the proportion of low-2CSL grain boundaries reached 80%, the amount of 23 grain boundaries could be up to 80% in all the low-2CSL grain boundaries, the grain boundary character distribution was optimized. Large and abnormity shape grainclusters were formed. There were many annealing twins, multiple twins and special triple junctions in a big grain-cluster. Combining with the study of partly recrystallization samples and annealing twin-chains, it could beconcluded that the development of multiply twins was important to the enhancement of the proportion of low-2CSL grain boundaries.