Influence of single-pass caliber rolling on the microstructural evolution and mechanical properties of Mg–10Gd binary alloy

This study investigates the influence of varying rolling reduction on the evolution of microstructure and mechanical properties of Mg10Gd (in wt%) alloys by caliber rolling (CR). By increasing the rolling reduction from 45 % to 65 %, a uniform bimodal structure is obtained in which coarse grains (CGs) larger than 10 µm are surrounded by fine grains (FGs). The MgGd alloy subjected to 65 % reduction exhibits superior mechanical properties, i.e. yield strength (YS) of ~424 MPa, ultimate tensile strength (UTS) of ~500 MPa and elongation (El.) of ~3.3 %. The synergistic improvement in strength and ductility is primarily attributed to the combined effects of low-angle grain boundary (LAGB) strengthening, precipitation strengthening, and the coordinated deformation exhibited by the bimodal structure. In addition, caliber rolling also provides a novel approach for the design of Mg alloys with uniform bimodal structures that exhibit both high strength and ductility.