Influence of pH Values on Passive Film-induced Stress and Susceptibility to Stress Corrosion Cracking in 7050 Aluminum Alloy
QI Xing1,2, SONG Ren-guo1,2, QI Wen-juan1,2, JIN Ji-rong1,2, WANG Chao1,2, LI Hai1
1. School of Materials Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu, China;
2. Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164, Jiangsu, China
Abstract：The change tendency of passive film-induced stress and susceptibility to stress corrosion cracking (SCC) with various pH values of 7050 aluminum alloy in 3.5% (mass fraction) NaCl solution was investigated by slow strain rate testing (SSRT) and flowing stress differential method. The results show that when pH≤7, with the increase of pH value, the passive film-induced stress and the susceptibility to SCC decrease, correspondingly; when pH>7, they increase with the increase of pH value. However, when pH=1,14, the corrosion type is exfoliation corrosion, the alloy matrix exfoliated, there is no film formed on the specimens surface. Moreover, the variation of passive film-induced stress is changed slowly when the pH value is between 6 and 9, nevertheless, it is much more severe when the pH value is between 2 and 5 as well as between 10 and 13. The whole variation plot is presented as valley shape and the passive film-induced stress and susceptibility to SCC is of a close relationship. The film-induced stress is related to the compositions of the passive film by X-ray photoelectron spectrum (XPS).
祁星, 宋仁国, 祁文娟, 金骥戎, 王超, 李海. pH值对7050铝合金膜致应力和应力腐蚀敏感性的影响[J]. 材料工程, 2016, 44(5): 86-92.
QI Xing, SONG Ren-guo, QI Wen-juan, JIN Ji-rong, WANG Chao, LI Hai. Influence of pH Values on Passive Film-induced Stress and Susceptibility to Stress Corrosion Cracking in 7050 Aluminum Alloy. Journal of Materials Engineering, 2016, 44(5): 86-92.
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