Utilizing atomic-scale grain boundary segregation: a new way for constructing the lamellar heterogeneous magnesium alloy

Heterogeneous structure significantly impacts the applications of wrought magnesium (Mg) alloys. Herein, we put forward a novel idea for constructing the heterogeneous structure by utilizing solute grain boundary (GB) segregation on recrystallization behavior during hot extrusion. The formation of heterogeneous structure is primarily attributed to the solute drag pressure (Al, Zn, and Ca), increasing solute atom levels co-segregation in GB, and the activation of non-basal <c+a> dislocations, which contribute to hindering continuous dynamic recrystallization. This study highlights the multi-scale solute atom GB segregation behavior and provides new insights into GB segregation-induced heterogeneous structural transition in Mg alloy.