Microstructure evolution and mechanical properties of aging 6061 Al alloy via laser shock processing

Microstructural evolution and mechanical properties of an aging 6061 Al alloy subjected to laser shock processing treatment (post-aging LSP treatment) were investigated by transmission electron microscopy (TEM) and mechanical tests. Results showed that the precipitates formed during aging treatment still remained, and the grain was refined by the ultra-high plastic strain plastic deformation during subsequent LSP treatment. Moreover, the precipitates effectively interacted with the dislocations induced by LSP. These typical microstructures contributed to the improvement in mechanical properties of the Al alloy. Relatively higher microhardness and strength were observed for the post-aging LSP Al sample. Furthermore, the synergistic strengthening mechanism involving the interaction of precipitate with dislocation, dislocations, and refined grains were clearly revealed.