Microstructure, Texture and Mechanical Properties of Magnesium Alloys Processed by Multi-Directional Forging: A Review

Magnesium (Mg) and its alloys are currently the lightest structural metals in engineering applications, widely used in aerospace, defense technology, transportation and electronic 3C fields. Plastic deformation is a commonly used method to improve the comprehensive mechanical properties of Mg alloys. Multi-directional forging (MDF), as a severe plastic deformation (SPD) method, is considered as an effective technology for manufacturing large-sized Mg alloys with high strength and toughness. This paper outlines the process principle of MDF and analyzes the microstructure evolution, texture and mechanical properties of Mg alloys processed by MDF. The effect of deformation parameters, such as deformation temperature, accumulative strain and strain rate, and alloying elements on grain refinement, second phase evolution and texture are discussed systematically. Additionally, recent research highlights the Mg alloys with high strength and toughness processed by MDF. Furthermore, the contribution of grain refinement, precipitation, solid solution and texture-strengthening mechanisms on the mechanical properties are revealed. Finally, we conclude the research progress, analyze the shortcomings in development, and recommend further prospects. We hope this review will inspire new ideas on the development of Mg alloys with a high strength and MDF process.