Microstructure and mechanical properties of laser high-velocity impact welded Ta/Cu joints

In this study, a laser high-velocity impact welding of Ta/Cu metal foil was successfully realized under different laser energies and flight distances. The morphology, microstructure, and mechanical properties of welded specimens were investigated via systematic experiments. Results indicated that the plastic deformation of the welded specimens was further pronounced with the increase in laser energy or flight distance. The welding area was ring-shaped, and the variation laws of the effective welding area under different laser energies and flight distances were summarized. The transition of the interface waveform was different when changing the laser energy and flight distance. Energy dispersive spectroscopy results showed that a trace element diffusion formed at the welding interface and intermetallic compounds were absent. Nanoindentation hardness tests showed that the hardness value increased with the decrease in distance from the welding interface. Two main failure modes of the Ta/Cu welding specimens occurred in the tensile shear tests, and the trend of the maximum tensile force under different process parameters was concluded.