Effect of retrogression re‐aging treatment on the stress corrosion behavior of the 7075 Al–Zn–Mg–Cu alloy. Issue 7 (19th February 2022)

• Record Type: Journal Article
• Authors: Liu, Jinqiu; Guo, Fuqiang; Wu, Dongting; Matsuda, Kenji; Wang, Tao; Zou, Yong
• Is Part Of: Materials and corrosion. Volume 73:Issue 7(2022)
• Page Start: 1074
• Page End: 1084
• Publication Date: 2022-02-19
• Subjects: 7075 Al–Zn–Mg–Cu alloy -- electrochemistry -- retrogression re‐aging treatment -- stress corrosion; Materials -- Periodicals; Metals -- Periodicals; Corrosion and anti-corrosives -- Periodicals; 620.1122305
• DOI: 10.1002/maco.202112730
• Languages: English
• ISSNs: 0947-5117

Abstract

Abstract: This paper studies the influence of the regression re‐aging (RRA) process on the mechanical properties and corrosion resistance of 7075. In the RRA heat treatment, the material properties are markedly affected by the variation of parameters in the regression stage. When the regression temperature and the regression duration increase, the mechanical properties of the material decrease. There was no intergranular corrosion in the samples treated by RRA, while obvious intergranular corrosion occurred in the T6 sample. Compared with the T6 sample, the RRA‐190‐0.5 sample with optimized parameters has a higher density of the precipitated phase and narrower precipitate‐free zone, and the precipitated phase along the grain boundary is discontinuous, isolated, and short. Compared with the single‐stage peak aging treatment, the RRA treatment can considerably improve the corrosion resistance and stress corrosion resistance but slightly reduce the strength. The best heat treatment process condition is 120°C/24 h + 190°C/0.5 h + 120°C/24 h. Abstract : Compared with the single‐stage peak aging treatment, the regression re‐aging (RRA) treatment can considerably improve the corrosion resistance of the 7075 aluminum alloy. Compared with the T6 sample, the RRA sample with optimized parameters has a higher density of the precipitated phase and narrower precipitate‐free zone, and the precipitated phase along the grain boundary is discontinuous, isolated, and short.