一种高纯Al-Zn-Mg-Cu合金在非等温时效过程中力学性能、抗局部腐蚀性能和显微组织的演变
Evolution of mechanical properties,localized corrosion resistance and microstructure of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging
戴轩轩 1李玉章 2刘胜胆 1叶凌英 1包崇军3
作者信息
- 1. School of Materials Science and Engineering,Central South University,Changsha 410083,China;Key Laboratory of Lightweight and High-strength Structural Materials,Changsha 410083,China;Key Laboratory of Non-ferrous Metals Science and Engineering(Ministry of Education),Changsha 410083,China
- 2. School of Materials Science and Engineering,Central South University,Changsha 410083,China;Kunming Metallurgical Research Institute Co.,Ltd.,Kunming 650031,China
- 3. Kunming Metallurgical Research Institute Co.,Ltd.,Kunming 650031,China
- 折叠
摘要
本文通过硬度测试、导电率测试、室温拉伸、晶间腐蚀、剥落腐蚀、慢应变速率拉伸和电化学测试研究了一种高纯Al-Zn-Mg-Cu合金在非等温时效过程中力学性能和抗局部腐蚀性能的演变规律,结合金相显微镜、电子背散射衍射、扫描电子显微镜和扫描透射电子显微镜等分析手段探讨相关机理.非等温时效处理包括从40℃以20℃/h升至180℃的升温阶段和从180℃以10℃/h降至40℃的降温阶段.结果表明,在升温阶段,温度的升高有利于强化相的形核与长大和GPI区向η′相的转变,因而试样的硬度和强度迅速增加.随后的降温时效阶段,η′相的尺寸进一步增加,数量密度变化不大,试样的硬度和强度略有增加.随着非等温时效时间的延长,试样的腐蚀形貌从开始的均匀层状腐蚀形貌转变为波浪状腐蚀形貌,腐蚀沿晶界和亚晶界扩展的速率和最大腐蚀深度逐渐降低,抗局部腐蚀性能逐渐提高,基于晶界析出相和亚晶界析出相的结构特征和化学成分分析探讨了其原因.
Abstract
The evolution of mechanical properties,localized corrosion resistance of a high purity Al-Zn-Mg-Cu alloy during non-isothermal aging(NIA)was investigated by hardness test,electrical conductivity test,tensile test,intergranular corrosion test,exfoliation corrosion test,slow strain rate tensile test and electrochemical test,and the mechanism has been discussed based on microstructure examination by optical microscopy,electron back scattered diffraction,scanning electron microscopy and scanning transmission electron microscopy.The NIA treatment includes a heating stage from 40℃to 180℃with a rate of 20℃/h and a cooling stage from 180℃to 40℃with a rate of 10℃/h.The results show that the hardness and strength increase rapidly during the heating stage of NIA since the increasing temperature favors the nucleation and the growth of strengthening precipitates and promotes the transformation of Guinier-Preston(GPI)zones to η′ phase.During the cooling stage,the sizes of η′ phase increase with a little change in the number density,leading to a further slight increase of the hardness and strength.As NIA proceeds,the corroded morphology in the alloy changes from a layering feature to a wavy feature,the maximum corrosion depth decreases,and the reason has been analyzed based on the microstructural and microchemical feature of precipitates at grain boundaries and subgrain boundaries.
关键词
Al-Zn-Mg-Cu合金/非等温时效/力学性能/抗局部腐蚀性能/显微组织Key words
Al-Zn-Mg-Cu alloy/non-isothermal aging/mechanical properties/localized corrosion resistance/microstructure引用本文复制引用
基金项目
Department of Science and Technology of Yunnan Province,China(202302AB080024)
出版年
2024
NETL
NSTL
万方数据