Effect of variable-rate non-isothermal aging on microstructure, mechanical properties, and corrosion behavior of Al–Zn–Mg alloy

Abstract

A comprehensive study was conducted to evaluate the effects of non-isothermal aging (NIA) processes with varying rates on the microstructure, mechanical properties, and corrosion resistance of an Al-7.6Zn-2.4Mg-0.2Cu-0.2Cr-0.5Mn-0.15Zr alloy. Compared to traditional T6 and RRA processes, the NIA process offers unique advantages in optimizing alloy performance. The N10-30 process achieves a superior balance between strength and ductility, with a yield strength of 533 MPa and an elongation of 12.7 %, while reducing the aging time by 66 % compared to T6, resulting in significant energy savings and enhanced practicality for structural applications. The N30-10 process exhibits excellent corrosion resistance due to the discontinuous distribution of grain boundary precipitates and the formation of an optimal precipitation-free zone. This study demonstrates that non-isothermal aging processes with variable rates enable improvements in mechanical properties and corrosion resistance, along with significant reductions in both aging time and energy expenditure, thus contributing valuable knowledge for the advancement of 7xxx alloys.