Influence of holding time on microstructure and shear strength of Mg–Al alloys joint diffusion bonded with Zn–5Al interlayer

Abstract

Diffusion bonding with an elaborate interlayer design is one of the most promising methods to join dissimilar metals, where the quality of joint relies on the processing parameters strictly. In the present study, the influence of holding time on the microstructure and shear strength of Mg/Al alloys joint diffusion bonded with an interlayer of Zn–5Al was focused on. According to the experimental data obtained from microstructure, components distribution, shear strength testing and fracture analysis, it is found that when fixing diffusion temperature at 365°C, the shorter holding time led to the formation of phase structure composed of soft Al rich solid solution particles dispersing on the MgZn₂ base phase, which exhibits much better shear strength than the microstructures formed with longer holding time. For the case of 3 s holding time, the highest shear strength attained was up to 86·10 MPa.