超高纯铁素体不锈钢在3．5％NaCl中的腐蚀疲劳的裂纹萌生

本文利用三电极技术研究了超高纯铁素体不锈钢Ｆｅ－２６Ｃｒ－１Ｍｏ在３．５％ＮａＣｌ水溶液转化体系中，低周腐蚀疲劳的裂纹萌生行为．在静态点蚀电位以下，形变诱发点蚀出现，但是点蚀在本文的研究体系不是导致裂纹萌生的原因．在低应变速率下，裂纹沿晶内的驻留滑移带萌生，且沿滑移带的电化学溶解加快了裂纹萌生．在高应变速率下，裂纹在晶界萌生，且沿晶界有点蚀实验结果表明，电化学溶解加速了裂纹萌生，点蚀在此钝化体系中不是裂纹萌生的机制．应变速率影响裂纹萌生方式．

CRACK INITIATION OF SUPERPURE STAINLESS STEEL DURING LOW CYCLE CORROSION FATIGUE IN 3.5% NaCl SOLUTION

The behaviour of crack initiation of superpure stainless steel in 3.5% NaCl solution during low cycle corrosion fatiguing was studied by using three-electrode technique.The deformation may induce pitting at the passive potential which is less than the static pitting potential, but pitting was not found to initiate cracks. At low strain rate, the cracks were observed to initiate along the persistent slip bands(PSBs), and the electrochemical etching occurred at the PSBs. At high strain rate the cracks initiated at grain boundaries were obsereved. The results showed that the electrochemical dissolution accelerated the crack initiation process. and pitting at the localized deformed sites did not form the cracks at the passive system. And the strain rate affected the crack initiation mode.