The grain size,textures and grain boundary plane distributions in a cold-rolled and annealed ferritic stainless steel were investigated by means of EBSD techniques.The results show that,following cold rolling with the thickness reduction of 85%,relatively low temperature(780°C)annealing brings an extremely sluggish grain growth and no grain texture develops when the annealing time varies from 5min to 480min.The free energy reduction of the system is mainly caused by the grain boundary plane re-orientation in addition to minor grain growth because the distributions of grain boundary planes are moderately preferred on{100}according to the five parameter analyses(FPA)concerning the grain boundary plane characteristics.However,in the case of high-temperature(1000°C)annealing,the average grain size does not increase until annealing time is prolonged to 90 min,after which extensive grain growth occurs and strong{100}texture emerges whereas nearly random grain boundary plane distributions are observed.The free energy reduction of the system is most likely attributed to the selective growth.
采用电子背散射衍射(Electron-back scatter diffraction,EBSD)技术对比研究了小形变冷轧(厚度减缩量6%)304不锈钢经低温退火和高温退火后的晶界特征分布。结果表明,相比于轧制前的再结晶状态,轧制变形后的高低温退火处理都在一定程度上提高了合金中低Σ重位点阵(Coincidence site lattice,ΣCSL)晶界的比例,增幅均达20%以上;但在其晶界特征分布(grain boundary character distribution,GBCD)中,互成Σ3n取向关系的晶粒团簇(Cluster of grains with Σ3n relationship,Σ3n CG)大小和其外围一般大角度晶界(random high angle grain boundary,HAB)网络的连接特性却存在明显差异。低温退火样品中Σ3n CG尺寸比高温样品大得多,且其HAB网络连通性被低ΣCSL晶界阻断的效果也明显优于高温退火样品。进一步对两个样品的织构和残余亚结构进行对比分析后认为,形变诱发晶界的优先迁移是低温退火样品中获得较大尺寸Σ3n CG和HAB网络连通性被低ΣCSL晶界有效阻断的重要原因。
