Towards designing high mechanical performance low-alloyed wrought magnesium alloys via grain boundary segregation strategy: A review

Low-alloyed magnesium (Mg) alloys have emerged as one of the most promising candidates for lightweight materials. However, their further application potential has been hampered by limitations such as low strength, poor plasticity at room temperature, and unsatisfactory formability. To address these challenges, grain refinement and grain structure control have been identified as crucial factors to achieving high performance in low-alloyed Mg alloys. An effective way for regulating grain structure is through grain boundary (GB) segregation. This review presents a comprehensive summary of the distribution criteria of segregated atoms and the effects of solute segregation on grain size and growth in Mg alloys. The analysis encompasses both single element segregation and multi-element co-segregation behavior, considering coherent interfaces and incoherent interfaces. Furthermore, we introduce the high mechanical performance low-alloyed wrought Mg alloys that utilize GB segregation and analyze the potential impact mechanisms through which GB segregation influences materials properties. Drawing upon these studies, we propose strategies for the design of high mechanical performance Mg alloys with desirable properties, including high strength, excellent ductility, and good formability, achieved through the implementation of GB segregation. The findings of this review contribute to advancing the understanding of grain boundary engineering in Mg alloys and provide valuable insights for future alloy design and optimization.