中文摘要：

采用电化学阻抗和慢应变速率方法,结合扫描电子显微镜,研究了不同阴极极化电位下X80钢在鹰潭土壤模拟溶液中的应力腐蚀行为。结果表明：鹰潭土壤模拟溶液中,X80钢/溶液界面处电荷转移电阻随阴极极化程度增加先升后降。在自腐蚀电位条件下开裂机理为阳极溶解,当外加电位为-1000 m V（vs SCE）,应力腐蚀敏感性最低,此电位为最佳保护电位;继续增大阴极极化程度,应力腐蚀敏感性增加,此时开裂机制为氢和应力协同作用下的氢致开裂。

英文摘要：

The stress corrosion cracking （SCC） of X80 steel in a simulated soil solution of Yingtan area at Southeast China under cathodic polarization was studied by means of electrochemical imped- ance spectroscopy, slow strain rate test and scanning electron microscope. The results show that the charge transfer resistance at the steel/solution interface first rises then falls. The cracking mecha- nism of X80 steel is anodic dissolution under the open circle potential with the potential moving negatively. The SCC reaches a minimum at- 1000 mV （vs SCE）, which is the optimum protection potential. As the level of cathodic polarization continuously raises, the SCC sensitivity increases. The cracking mechanism of X80 steel is hydrogen induced cracking under the synergistic effect of stress and hydrogen when the applied potential lower than -1100 mV （vs SCE）.