时效处理对不同晶粒组织Al-Zn-Mg合金腐蚀性能的影响  

Effect of aging treatment on the corrosion performance of Al-Zn-Mg alloys with different grain structures

作　　者：王鹏宇 叶凌英[1,2,3] 柯彬[1] 董宇 刘胜胆[1,2,3] WANG Pengyu;YE Lingying;KE Bin;DONG Yu;LIU Shengdan(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Key Laboratory of Nonferrous Metal Materials Science and Engineering,Ministry of Education,Central South University,Changsha 410083,China;Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,Central South University,Changsha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]中南大学教育部有色金属材料和工程重点实验室,湖南长沙410083 [3]中南大学有色金属先进结构材料与协同创新中心,长沙410083

出　　处：《中南大学学报（自然科学版）》2024年第1期55-68,共14页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2022YFB3403700);河南省紧固连接技术重点实验室资助项目(JGLJ2208)。

摘　　要：以中强Al-Zn-Mg合金为研究对象,采用晶间腐蚀、电化学极化曲线测试、慢应变速率拉伸等试验,结合OM、TEM、SEM、EBSD等组织分析方法研究时效处理和晶粒组织对合金腐蚀性能的影响。研究结果表明:随着双级时效时间的延长,再结晶晶粒合金的抗腐蚀性能逐渐提升,从欠时效处理到过时效处理,晶间腐蚀等级由4级降为2级,电化学腐蚀电流密度由27.71μA/cm^(2)降为0.098μA/cm^(2),应力腐蚀指数由79.15降至18.40;纤维晶粒合金与同时效阶段的再结晶晶粒合金相比,其抗腐蚀性能显著提升,其中,晶间腐蚀最大深度降低了35.9%,电化学腐蚀电流密度降低了81.4%,年腐蚀速率降低了81.9%,应力腐蚀敏感指数降低了46.2%。中强Al-Zn-Mg合金腐蚀性能的提升主要源于其较低的再结晶分数和较低的大角度晶界占比。The effects of aging treatment and grain structure on the corrosion performance of the alloy were investigated by using the medium-strength Al-Zn-Mg alloy as the research object,and using intergranular corrosion,electrochemical polarization curve test,and slow strain rate tensile tests,combined with OM,TEM,SEM,and EBSD observations,respectively.The results show that the corrosion resistance of the recrystallized grain alloy gradually improves with the extension of the double-stage aging time,the intergranular corrosion grade decreases from grade 4 to grade 2,the electrochemical corrosion current density decreases from 27.71μA/cm^(2) to 0.098μA/cm^(2),and the stress corrosion sensitivity factor decreases from 79.15 to 18.40 when the treatment method changes from the under-aging treatment to the over-aging treatment.The corrosion resistance of the fiber grain alloy is significantly improved compared with that of the recrystallized grain alloy at the same aging stage,including a 35.9%reduction in the maximum depth of intergranular corrosion,an 81.4%reduction in the electrochemical corrosion current density,an 81.9%reduction in the annual corrosion rate,and a 46.2%reduction in the stress corrosion sensitivity index.The improvement in corrosion performance is mainly due to the lower recrystallization fraction and lower percentage of large-angle grain boundary of the medium-strength Al-Zn-Mg alloy.

关 键 词：AL-ZN-MG 晶粒组织 腐蚀性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]