Recent progress in preparation of bimodal grain structure and improvement of mechanical and corrosion properties of magnesium alloys

Nowadays, magnesium (Mg) alloys are increasingly being considered as a promising lightweight structural material because of their inherent low density and high specific strength. However, the broad application of most Mg alloys is limited by their poor strong-ductility trade-off at room temperature. At present, tailoring the bimodal grain structure (BGS) has the potential to concurrently enhance strength and ductility. Therefore, in order to achieve controllable preparation of BGS, recent research on the formation of Mg alloy with BGS was evaluated from the perspectives of alloy design, initial microstructure of billets, and process parameter. In addition to summarizing the role of BGS in synergistically improving strength and ductility, the influence of BGS on other properties of Mg alloys was also summarized, such as tension-compression yield asymmetry, corrosion resistance, fatigue performance, and fracture toughness. The research progress in controlling BGS provides valuable insights into the design and production of high-performance Mg alloys.