Experimental and numerical study on the laser shock welding of aluminum to stainless steel

This study aims to verify that the welding between Al foil and SS foil can be obtained through laser shock welding (LSW). It also seeks to investigate the characteristics of interface wave, as well as the formation mechanism of wave in LSW. The Al/SS welding combination was found to have better welding effects than the SS/Al welding combination. The process window of the two parameters of laser pulse energy and flight distance was obtained experimentally. Results showed that the wavelength and amplitude of the interface wave gradually increased along the welding direction, that is, the radial direction of the center of the welding spot. Experiments and simulations revealed that the wave crest movement direction on the Al side with low density at the welding interface was opposite the welding direction. By contrast, the wave crest movement direction on the SS side with high density was consistent with the welding direction. Energy dispersive spectroscopy results showed that an element diffusion layer with a thickness of approximately 4.5 mu m formed at the Al/SS welding interface. No intermetallic compound was found to be generated at the interface. Results of the tensile shear test showed that the failure modes of welding were the interface failure and fracture failure of the welding joint edge. The wave characteristic, formation mechanism of waves, and welding characteristics at the interface were studied through numerical simulation with smoothed particle hydrodynamics.