7050铝合金应力腐蚀敏感性和钝化膜引起的膜致应力随电位变化的一致性

Consistent Variation of Stress Corrosion Cracking Susceptibility and Passive Film-induced Stress for 7050 Aluminum Alloy with

摘要:

用流变应力差值法测量了不同极化电位下7050铝合金在3.5%NaCl 水溶液（pH=10）腐蚀过程中表面钝化膜形成的拉应力，并用慢应变速率拉伸法测量了不同极化电位下的应力腐蚀敏感性。结果表明:7050铝合金在溶液中自然腐蚀时，表面钝化膜会产生一定的拉应力；阳极极化使表层拉应力明显上升，且随着电位升高应力增大；阴极极化时，当电位E ≥-1100mV时表层拉应力随着电位的升高而降低，当电位≤E-1100mV时拉应力随着电位升高而升高。应力腐蚀敏感性随外加电位变化规律和钝化膜引起的附加拉应力变化完全一致。

Abstract:

The film-induced stress and susceptibility to stress corrosion cracking (SCC) of 7050 aluminum alloy in the chloride solution at various potentials have been studied in this paper. The results showed that a large tensile stress was generated by the passive film during original corrosion. The passive film induced tensile stress increased obviously with an increase in potential under an anodic potential; however, it decreased with an increase in potential when the potential E≥-1100 mVSCE while it increased when E＜-1100 mVSCE under a cathodic potential. The variation of film-induced stress with potential was consistent with that of the susceptibility to SCC with potential.