Atomistic simulation on the formation mechanism of bonding interface in explosive welding

Explosive welding can join a wide variety of both similar and dissimilar metals. However, because of the extremely fast welding process and micro-sized interfacial morphologies, it is a challenge to experimentally acquire the complete dynamic microscopic information. In this paper, the formation of the bonding interface was modeled through molecular dynamics simulations. Three significant phenomena, including a flat/wavy interface, wave formation, and fine grains, were investigated. The simulation results demonstrate that a flat interface is formed in the solid-state welding while a wavy interface is produced in the liquid-state welding. The wave formation can be explained by the jet that sequentially impacts the flyer plate and the base plate. There are two different pathways to form fine grains. At the regions of the bonding interface and the vortex, the fine grains are generated after the cooling process. Away from the bonding interface, the fine grains are produced by the drastic collision between the jet and the bonding surfaces.