极化和频率对A537钢在3.5%NaCl溶液中的腐蚀疲劳裂纹扩展行为的影响

利用三电极技术研究了极化和频率对A537低合金钢在3.5%NaCl活化体系的腐蚀疲劳的裂纹扩展行为,包括对裂纹扩展速率和断口形貌的影响.结果表明,在活化体系中,强极化条件,频率越小,裂纹扩展速率越大;在阴极保护条件下,频率对裂纹扩展速率的影响很小.阳极溶解和阴极析氢可以增加裂纹扩展速率.裂尖析氢量的大小决定了断口解理面大小.在裂尖塑性区内的位错结构为胞结构,而在塑性区外为长位错线

EFFECT OF POLARIZATION AND FREQUENCY ON CRACK PROPAGATION BEHAVIOR OF A537 STEEL IN 3.5% NaCl SOLUTION

The effect of polarization and frequency on the crack propagation behavior including crack propagation rate(CPR) and fracture surface was studied. The results showed that in A537/3.5%NaCl active system CPR increased with the decrease of frequency under serious polarization condition, but under cathodic protection condition, frequency had no effect on CPR. The anodic dissolution and hydrogen embrittlement can increase CPR. The amount of hydrogen evolution can affect the area of clevage surface. The dislocation was cell structure at the plastic zone of crack tip, but long dislocation line at the region beyond the plastic zone.