Gradient microstructure evolution in laser shock peened Ti6Al4V titanium alloy

The microstructures at different depths of Ti6Al4V alloy induced by laser shock peening (LSP) are comprehensively characterized using TEM, EBSD and XRD. The results show that LSP can introduce a gradient microstructure in the surface layer of Ti6Al4V alloy. The evolution mechanism of this gradient microstructure is elucidated. To explore the intrinsic relationship between gradient microstructure and mechanical properties, the corresponding microhardness values are estimated based on the microstructure at different depths. Besides, the synergistic strengthening mechanism of the gradient microstructure is revealed.