时效工艺对轧制态7075铝合金耐蚀性能的影响

Effect of aging process on corrosion behavior of rolled 7075 aluminum alloy

采用光学显微镜、电化学测试技术、慢应力应变拉伸（SSRT）方法以及扫描电镜研究了不同时效工艺对轧制态7075铝合金微观组织和腐蚀行为的影响。结果表明：不同时效工艺处理后,轧制态7075铝合金在1.5%NaCl溶液中的极化曲线均表现出钝化特征;单级时效的合金,晶界呈连续分布,强度最大,耐蚀性和抗应力腐蚀开裂（SCC）敏感性最差;双级时效的合金,晶界呈断续分布,强度有所减小,耐蚀性和抗SCC敏感性增强;三级时效的合金,具有再结晶组织,晶界呈断续分布,既具有单级时效的强度,又具有最好的耐蚀性和抗SCC敏感性。

Effects of different aging processes on microstructure and corrosion behavior of rolled 7075 aluminum alloy were investigated by means of optical microscope,electrochemical analysis,stranded slow strain rate tensile test（SSRT） and scanning electron microscopy（SEM）.The results show that the polarization curves of the alloy in 1.5% sodium chloride solution exhibit the passivation characteristics after different aging treatments.The alloy after single-stage aging exhibits continuous grain boundary distribution,maximum strength,and the worst susceptibility to corrosion resistance and stress corrosion cracking（SCC）.After two-stage aging,the grain boundary of the alloy is distributed intermittently,the strength decreases,the corrosion resistance and the sensitivity of SCC resistance are enhanced.The alloy after three stage aging has recrystallized structure,and the grain boundary is distributed intermittently,and it has both the strength of single stage aging and the best corrosion resistance and anti SCC sensitivity.