Modeling the evolution of intermetallic compounds at the weld interface of Al-Mg dissimilar joint obtained via solid-state joining for applications in the automotive and aerospace industry

Industries are seeking sustainable solutions, which has prompted the adoption of lightweight materials, such as aluminum and magnesium, in the aerospace and automotive industries. Joining dissimilar materials, such as aluminum and magnesium, offers the potential for multi-material structures with the synergy of the desirable properties. However, the excessive formation of intermetallic compounds at the joint interface can negatively affect its mechanical properties. Solid-state joining techniques offer a solution, as they operate at lower temperatures, which limits intermetallic compound thickness. Combining numerical techniques, such as the finite-element and multiphase-field methods, can facilitate intermetallic compound evolution investigation during solid-state joining processes. This study employs the former to simulate the refill friction stir spot welding process for joining aluminum and magnesium and the latter to investigate the evolution of intermetallic compounds at the joint interface. The process simulation provides a temperature and strain profile at the joint interface, which drives the evolution of intermetallic compounds. The multiphase-field model is used to analyze the morphology and kinetics of the intermetallic compound under driving forces, such as chemical and mechanical effects. Various parameters, such as interface energy, grain boundary diffusion, and initial microstructure, are examined and demonstrated to impact the final morphology and kinetics of the intermetallic compounds. Combining such numerical techniques offers a framework for studying intermetallic compound evolution in various solid- state joining processes and material systems.