In this paper, the effect of cathodic polarization on corrosion behavior of AA7003 under three kinds of aging treatments (including peak aging (PA), double peak aging (DPA) and regression re-aging (RRA)) was studied in 3.5 wt％ sodium chloride solution through slow strain rate testing(SSRT) and electrochemical testing. X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods were also applied to investigating corrosion behavior and fracture morphology. The results showed that under open circuit, stress corrosion cracking (SCC) of AA7003 might by classified as anodic dissolution. In this case, the extent of SCC susceptibility (ISCC) of AA7003 alloy with different aging treatments was as follows:ISCC(PA)>ISCC(DPA)>ISCC(RRA). On the other hand, stress corrosion cracking (SCC) of AA7003 under cathodic polarization might be classified as hydrogen embrittlement (HE) which had been proved in this paper by presence of AlH3 diffraction peak in XRD patterns. In this case, for AA7003 with any of the three aging treatments, hydrogen embrittlement susceptibility (IHE) increases with negatively shifting of cathodic polarization.%采用电化学腐蚀试验与不同阴极极化电位下的慢应变速率拉伸试验,并结合XRD衍射图谱分析及SEM断口形貌观察,研究了阴极极化对峰时效(PA),双峰时效(DPA)以及回归再时效(RRA)7003铝合金在3.5％NaCl溶液中应力腐蚀类型的影响.结果表明,在开路电位下7003铝合金的应力腐蚀主要由阳极溶解控制,应力腐蚀敏感性ISCC(PA)>ISCC(DPA)>ISCC.而在外加阴极电位的情况下XRD衍射谱中出现AlH3衍射峰,断口形貌则表现出沿晶及解理倾向,说明应力腐蚀转变为由氢脆控制,且氢脆敏感性(IHE)随着极化电位的负移而不断增加,其中3种时效状态的敏感性顺序为:IHE(PA)>IHE(DPA)>IHE(RRA).
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