中文摘要：

通过晶界工程（GBE）处理，可使304不锈钢样品中的低∑CSL晶界比例提高到70％（Palumbo—Aust标准）以上，同时形成了大尺寸的“互有∑3^n取向关系晶粒的团簇”显微组织．采用C型环样品恒定加载方法，在pH值为2．0的沸腾20％NaCl酸化溶液中进行应力腐蚀实验．GBE样品在平均浸泡472h后出现应力腐蚀裂纹，SEM，EBSD和OM分析表明，应力腐蚀开裂（SCC）为沿晶开裂（IGSCC）和穿晶开裂（TGSCC）的混合型．而未经GBE处理的样品在平均浸泡192h后出现多条应力腐蚀主裂纹，且多为沿晶界裂纹．经过GBE处理的样品中大尺寸的晶粒团簇及大量相互连接的∑3-∑3∑9和∑3∑9—227等∑3^n类型的三叉界角，阻碍了IGSCC裂纹的扩展，从而提高了304不锈钢样品的抗IGSCC性能．

英文摘要：

The grain boundary network in a 304 stainless steel can be controlled by grain boundary engineering （GBE）. The total length proportion of ∑3^n coincidence site lattice （CSL） boundaries was increased to more than 70%, and the large size highly twinned grain-cluster microstructure formed through the treatment of GBE. Stress corrosion cracking （SCC） susceptibility of 304 stainless steel was evaluated through C ring specimen tests conducted in acidified boiling 20%NaCl solution. Based on the characterization by SEM, EBSD and OM, it was found that the large grain-clusters associated with many interconnected ∑3-∑3∑9and∑3∑9-227 triple junctions produced by GBE arrest the IGSCC cracks and improve the resistance to IGSCC.