304不锈钢冷轧退火∑3^n特殊晶界分布研究

∑3^n SPECIAL BOUNDARY DISTRIBUTIONS IN THE COLD-ROLLED AND ANNEALED 304 STAINLESS STEEL

采用电子背散射衍射（EBSD）技术研究了固溶处理的304不锈钢经6％-50％冷轧变形后在1173K下进行长时间（24—96h）退火后的晶界特征分布（GBCD）．结果表明，经小变形（约6％）冷轧退火后的样品出现了较多的∑3^n（n=1，2，3）特殊晶界，较好地隔断了一般大角度晶界网络的连通性．通过基于EBSD的单一截面迹线法对共格和非共格∑3晶界进行了区分测定，显示被优化的晶界特征分布中，非共格∑3孪晶界是其主要部分．进一步分析指出，非共格∑3晶界的迁移和反应与基于退火孪晶的中低层错能金属材料GBCD优化密切相关．

Grain boundary character distributions （GBCD） in the 304 stainless steel cold rolled and then annealed at 1173 K were analyzed by electron back scatter diffraction （EBSD）. The results showed that under low strain （about 6%） followed by long-time annealing （24-96 h） the special boundaries with a higher fraction of ∑3^n（ in=1, 2, 3） boundaries appeared, and the connectivity of general high angle grain boundary （HAB） network was interrupted by ∑9 and ∑27 segments. Incoherent and coherent ∑3 boundaries were identified by single-section trace analysis method, which showed that the major part of ∑3 boundaries was incoherent one in the optimized GBCD. Further discussion pointed out that the migration and interaction of incoherent ∑3 boundaries are relative to the twin-induced GBCD optimization.