Influence of post-weld heat treatment on microstructure and adhesion of Ti/Cu composite

It is well known that brittle interfacial intermetallics are typically present in laminated composites and degrade their mechanical performance. To investigate the relationship between intermetallics and mechanical properties, Ti/Cu-laminated composite plates prepared by explosive welding were studied with different heat treatments. A transition layer containing four zones of intermetallic phases, Cu 4 Ti, Cu 4 Ti 3 , CuTi, and CuTi 2 , was found at the interface between Ti and Cu after explosive welding. The intermetallics became thicker as the temperature of the heat treatment increased, especially for the CuTi phase. The sample treated at 473 K exhibited the highest bonding strength of 199.7 MPa, which was attributed to the elimination of residual stress during the welding and the diffusion of copper to improve interfacial bonding.