The inherently poor corrosion resistance and low formability of magnesium (Mg) alloys fundamentally constrain their wider application, particularly the challenge of simultaneous enhancement. In this work, we fabricate a low-alloyed Mg-1Sm-0.8Mn-0.5Ca-0.4Zn extruded alloy and specifically focus on the influence of the existing states of Ca in the microstructure. By developing a simple heat treatment to effectively tailor Ca into grain boundary segregation, we propose a novel strategy that synergistically enhances both corrosion resistance and formability potential — achieving an exceptional combination of low corrosion rate (0.35 mm y -1 ), high elongation (46%), and large yield-to-tensile strength difference (91 MPa). The results demonstrate that the transition of Ca from Mg 2 Ca phase to grain boundary segregation substantially suppresses micro-galvanic corrosion, nearly doubling the corrosion resistance. Furthermore, studies reveal that Ca-segregated grain boundaries effectively activate pyramidal slip at one side of the grains with low m ' value, contributing to the enhanced ductility. This study provides important insights for the development of Mg alloys with high corrosion resistance and high formability.
Bao et al. (Wed,) studied this question.