Effect of grain characteristics on stress corrosion resistance of a novel Al-Mg-Zn-Si alloy with high Mg content

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For next-generation high-performance aluminum alloys , Al-Mg-Zn-Si alloy has excellent potential for development. This paper investigates the stress corrosion resistance of a novel Al-8.5Mg-3.0Zn-0.25Si alloy with high Mg content, focusing on varying recrystallization degrees and grain morphologies. The results indicate that as the recrystallization degree decreases, the index of slow strain rate testing drops by 36 % and the self-corrosion current drops by 55 %. For the same recrystallization degree, the oxide film thickness of equiaxial grains is thicker than that of plate-like grains, with a 39 % reduction in the index of slow strain rate testing and better stress corrosion resistance . Furthermore, stress corrosion cracks mainly expand along the recrystallized grain boundaries, the greater the degree of recrystallization, the smoother the recrystallized grain boundaries, stress corrosion cracks are more easily extended. By examining the influence of different grain characteristics on the stress corrosion behavior of the alloy, this study offers theoretical insights and a scientific basis for enhancing the understanding of stress corrosion mechanisms and advancing large-scale industrial production in aerospace applications .