Influence of Artificial Aging of ZnAlCu Alloys on Microstructure and Compressive Yield Strength

So far, the influence of aging on the mechanical properties of ZnAlCu alloys has primarily been investigated under tensile load. Since some applications, such as plain bearings, are subjected to compressive loads, the results presented in the literature do not fully encompass all areas of application. Therefore, this publication focuses on the influence of artificial aging on the 0.2% compressive yield strength. Samples from ZnAl1Cu0.7, ZnAl11Cu0.7 and ZnAl11Cu2 were aged at different aging temperatures for up to 840 h. After different aging periods, compressive tests as well as microstructure investigations with SEM and XRD were carried out. Furthermore, the dimensional stability of ZnAl11Cu0.7 was investigated in a quenching dilatometer. Shrinkage of up to 0.08%, followed by swelling, was determined. Compressive tests revealed a decrease in the 0.2% compressive yield strength across all tested alloys, most pronounced at the beginning of the aging process, reaching an approximately constant strength level after an alloy- and temperature-dependent aging period. At the end, based on the results, a possible way to determine the constant strength level and the necessary aging time to reach this strength level for specific application temperatures is presented to ensure stable mechanical properties during operation.