Surface modification for AZ80 magnesium alloy by laser shock processing

The effect of pre-solution, pre-aging and post-aging on microstructure parameters (twins and precipitates) of laser shocked AZ80 magnesium alloy was investigated by pre-solution or pre-aging+LSP deformation+post-aging. The results show that the deformation band with high density twins in the strengthened layer is produced by the treatment of pre-solution+laser shock processing (LSP) deformation, and the twins density increases with decrease of the distance to the impacted surface. The deformation band with high density twins is still produced by treatment of aging treatment for 16 h under the temperature of 170℃ due to the stability of the residual compressive stresses. At the same time, a large number of granular β-Mg17Al12 phases are dispersively and preferentially precipitated in the deformation band, the twin interface and the twin lamellae where the stress concentration exists. The ratio of twinning in the strengthened layer is greatly reduced by the high density β phase precipitated from the pre-solution, and the volume fraction of the twins is decreased significantly, because of the high density dislocation and precipitates induced by LSP. © 2016, Central South University of Technology. All right reserved.