Effect of Pre-deformation on Aging Precipitation Process of 2E12 Aluminum Alloy

The effect of pre-deformation on the aging precipitation process of 2E12 aluminum alloy was investigated by DSC analysis, microhardness test and transmission electron microscope (TEM). The results show that the peak aging of 2E12 alloy exhibits two distinct stages. Pre-deformation weakens the hardening effect of the first aging stage, enhances the peak aging hardness and accelerates the aging process. The peak aging hardness increases and peak aging time decreases with more pre-deformation amount. Increase in pre-deformation degree also leads to finer and more dispersive S-lath in 2E12 alloy. The dislocations introduced by the pre-deformation provide preferential sites for the heterogeneous nucleation of S phase. The edge dislocation sites in dislocation loops are beneficial for nucleation of spherical S phase. Pre-deformation accelerates the precipitation of Type I S phase and delays the precipitation of Type II S phase.