Journal of Materials Science, Vol.55, No.16, 7052-7065, 2020
Influence of multi-axial compression pre-treatment on the microstructure evolution and mechanical properties of an Al-Cu-Li alloy during aging
The influence of multi-axial compression (MAC) pre-treatment on the microstructure evolutions and mechanical properties of an Al-Cu-Li alloy during aging was investigated by transmission electron microscopy, tensile tests and X-ray diffractometer. The results show that the aging kinetics and strength of the samples processed by MAC pre-treatment are significantly enhanced compared with those treated by the conventional T6 treatment during aging at 160 degrees C. The precipitation sequence for the T6 treatment is as follows: SSS -> G.P. zones + delta '/beta ' -> theta ' + delta '/beta ' -> delta '/beta ' + theta ' + T-1. However, the precipitation sequence during post-MAC aging changes to: SSS -> T-1 -> T-1 + theta '. After MAC pre-treatment, the number density of T-1 precipitates increases with decreased diameters and the precipitations of theta ' and delta '/beta ' are suppressed during the subsequent aging.