Effect of heat treatment on strength, exfoliation corrosion and electrochemical behavior of 7085 aluminum alloy

• Published in: Materials in engineering Vol. 35; pp. 93 - 98
• Main Authors: Chen, Songyi, Chen, Kanghua, Peng, Guosheng, Jia, Le, Dong, Pengxuan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2012
• Subjects: A. Non-ferrous metals and alloy; E. Corrosion; E. Mechanical; E. Corrosion; A. Non-ferrous metals and alloy; E. Mechanical
• ISSN: 0261-3069
• DOI: 10.1016/j.matdes.2011.09.033

► The effect of heat treatment on strength and exfoliation corrosion of the AA7085 has been studied. ► RRA increases exfoliation corrosion resistance without sacrificing the strength. ► DRRA improves exfoliation corrosion resistance with retention of strength. ► The HLA decreases the strength and corrosion resistance. The influence of heat treatment on strength, exfoliation corrosion and electrochemical behavior of 7085 aluminum alloy has been investigated by tensile testing, exfoliation corrosion testing, polarization curve and electrochemical impedance spectroscopy (EIS) combined with transmission electron microscope (TEM). The results show that retrogression and reaging (RRA) improved exfoliation corrosion resistance without sacrificing the strength compared to T6 temper. Dual-retrogression and reaging (DRRA) improved exfoliation corrosion resistance equivalent to T74 temper and maintained the strength similar to retrogression and reaging. The high-temperature and the subsequent low-temperature aging (HLA) decreased the strength and corrosion resistance compared to the T6 temper. The trends of corrosion resistance are further confirmed by polarization curve experiment and EIS test. The effect of heat treatment on strength and corrosion resistance is explained by the role of matrix precipitates and grain boundary precipitates, respectively.