Research progress of solid-phase welding technology between magnesium and dissimilar metals

Solid-phase welding of magnesium with dissimilar metals leverages the advantages of multi-material systems, enhances design flexibility of components, and promotes equipment lightweighting. Compared to fusion welding processes, solid-phase welding effectively suppresses defects such as pores, cracks, and brittle intermetallic compounds, enabling the production of high-quality joints. This review systematically examines the fundamental principles and technical challenges in solid-phase welding between magnesium and dissimilar metals (aluminum, steel, titanium, and copper). A comprehensive analysis is presented for five representative solid-phase welding technologies: friction stir welding, ultrasonic welding, magnetic pulse welding, diffusion bonding, and explosive welding. The discussion encompasses their underlying mechanisms, interfacial morphology characteristics, and research progress in mechanical properties of welded joints. A comparative evaluation is conducted from six critical perspectives: welding efficiency, welding quality, applicability, economic efficiency, environmental compatibility, and safety. Future research directions are proposed to advance this field: 1) Integration of machine learning approaches for precise control of welding process parameters; 2) Development of dynamic and in-situ observation techniques to refine transient solid-phase welding theories; 3) Technological innovation in solid-phase welding based on theoretical breakthroughs; 4) Establishment of systematic tracking and evaluation methodologies for service behavior of welded components and joints; 5) Integrating solid-state welding into high-volume manufacturing processes through the lenses of production efficiency, quality assurance, intelligent manufacturing, and sustainability. These recommendations aim to address current technical limitations and guide the evolution of next-generation solid-phase welding technologies for magnesium-based dissimilar metal systems.