Solute-Dislocation Binding and Solute Clustering as a Mechanism for Room Temperature Ductility and Formability of Mg Alloys

Abstract

Non-basal slips are important for ductility and formability of magnesium. Alloying elements can activate the non-basal slip by reducing critical resolved shear stress anisotropy among slip planes, and the optimum alloy contents in binary alloys can be estimated using atomistic simulations. The critical resolved shear stress anisotropy of multicomponent Mg alloys can be minimized if the content of alloying elements is adjusted so that the overall contribution to the dislocation binding intensity from the individual elements is equal to that of the binary alloy with the optimum alloy content. The activation of non-basal slips in multicomponent Mg alloys can be robust when an element with relatively weak dislocation binding is the main alloying element. Grain boundary segregation or solute clustering that can have an effect on the grain boundary mobility, recrystallization, and eventually the texture is another requirement for improved formability. The mechanism for the effect of grain boundary segregation or solute clustering on the texture evolution is discussed, and it is demonstrated that experiments confirm that the multicomponent Mg alloys satisfying the above criterion show higher room temperature tensile elongation and formability than other alloys.