Author(s)

Xingzhi Liao^1,2, Xiaohua Kong^1,2, Pengxuan Dong^1,2, Kanghua Chen^1,2,3

¹Science and Technology on High Strength Structural Materials Laboratory, Central South University, Changsha, China.
²Collaborative Innovation Center of Advance Nonferrous Structural Materials and Manufacturing, Central South University, Changsha, China.
³Light Alloy Research Institute, Central South University, Changsha, China.

By means of TEM, hardness, conductivity, tensile strength test, fracture toughness test, polarization curve and EIS, the Al-Zn-Mg-Cu alloys treated by a new multi-stage aging system, i.e. pre-aging, over-aging and re-aging (120°C/24h + 160°C/8h + 120°C/24h), were characterized. It is found that compared with the Al-Zn-Mg-Cu alloys treated by T76 (120°C/24h + 160°C/8h), the new multi-stage aging treatment can improve the tensile strength, fracture toughness, hardness and conductivity of the alloys at the same time. This is mainly due to the pre-aging, over-aging and re-aging process of super high strength aluminum alloys. Compared with the two-stage over aging process, the formation of multi-stage multi-phase precipitation structure can improve the strength, toughness and corrosion resistance of the alloys at the same time. The polarization curve is consistent with the conclusion. Therefore, we conducted this study to test how the comprehensive properties of the alloy can be improved.

Al-Zn-Mg-Cu-Zr Alloys, Pre-Aging, Over-Aging and Re-Aging, Exfoliation Corrosion, Electrochemical Corrosion

Liao, X. , Kong, X. , Dong, P. and Chen, K. (2020) Effect of Pre-Aging, Over-Aging and Re-Aging on Exfoliation Corrosion and Electrochemical Corrosion Behavior of Al-Zn-Mg-Cu Alloys. Journal of Materials Science and Chemical Engineering, 8, 81-88. doi: 10.4236/msce.2020.82008.