Dislocation configuration evolution of FCC alloys induced by Laser Shock Processing

Abstract

To investigate the relations between dislocation motion and microstructure evolution of FCC metals during Laser Shock Processing (LSP), and then improve the understanding of the mechanism of laser shock strengthening, aluminium alloy 2A02 and austenitic stainless steel 201 were selected as the representatives, and laser shocked by the Nd:YAG laser with 1064 nm output wavelength and 20 ns short pulse. The microstructure evolution of test materials induced by laser shock was analysed via Transmission Electronic Microscope (TEM) and Inverse Fast Fourier Transformation (IFFT), and the dislocation configurations and their function were discussed. The experimental results indicated that the increase in both the surface hardness and the residual compressive stress of the laser-shocked test materials can be attributed to the contribution of complex dislocation configurations and nano-crystallisation.