Impact welding process and microstructure of multi-layered Al-Cu joint by vaporizing foil actuator

A multi-layered Al-Cu joint is achieved by vaporizing foil actuator welding (VFAW). The process of welding, tensile properties and microstructure of multi-layered Al-Cu joint are systematically investigated using numerical simulations and experiments. Micro-melting at the welding interface contributes to metallurgical bonding. When the impact velocity exceeds 430 m/s, a larger metallurgical bonding area is created between the two neighbouring sheets, which in turn increases the shear strength of the joint. Comparing to the Cu-Cu interface, the Al-Cu interface forms a distinct waveform because of the differences between the base material in hardness and density. Due to the rapid cooling rate of VFAW, a gradient structure containing nanocrystals and amorphous zone is formed between the matrices and the transition zone.