(1. 中南大学 粉末冶金国家重点实验室，长沙 410083；
2. 中南大学 化学化工学院，长沙 410083)
摘 要: 采用循环极化、U型样法、慢应变速率拉升、金相表征等手段对比研究热处理制度对7150铝合金电化学腐蚀性能和应力腐蚀性能的影响；并从TEM晶界析出相分布、晶界腐蚀形貌、点蚀发生发展机理以及应力腐蚀开裂机制等角度，对电化学参数与应力腐蚀敏感性之间的一致性关系进行理论说明。结果表明:第二点蚀电位(φpit,2)及其相应电位差值(φpit,2-φcorr、φpit,2-φrep)随时效的变化趋势与耐应力腐蚀能力随时效的变化趋势完全一致。
关键字: 7150铝合金；第二点蚀电位；电位差；应力腐蚀敏感性；热处理
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:The influences of ageing processes on cyclic polarization and stress cracking corrosion (SCC) susceptibility were compared and investigated using cyclic polarization, U-type specimen method, slow strain rate tension and optical microscopy. Fundamental theoretical analysis behind the link pitting potentials and SCC susceptibility of 7150 Al alloys with different ageing processes was analyzed theoretically, based on grain boundary precipitates distribution revealed by TEM, corrosion morphology of grain boundary, initiation and propagation mechanisms of pitting corrosion and SCC mechanism. The results show that the trend of electrochemical parameters (the second pitting potential φpit,2 and potential differences, such as (φpit,2-φcorr) and (φpit,2-φrep)) as function of ageing process is same exactly with the trend of SCC resistance as function of ageing process.
Key words: 7150 Al alloy; second pitting potential; potential difference; stress cracking corrosion susceptibility; heat treatment
