Enhanced mechanical properties and rolling formability of fine-grained Mg-Gd-Zn-Zr alloy produced by equal-channel angular pressing

A fine-grained Mg-1.8Gd-1Zn-0.1Zr (at.%) alloy with long-period stacking ordered (LPSO) phase was obtained via solid-solution(SS) treatment plus multi-pass equal-channel angular pressing(ECAP). The effects of post-ECAP rolling on microstructure change and deformation characteristic of the Mg alloy were investigated. The results showed that the fine-grained alloy after 16 ECAP passes at 658 K had a yield strength of 334.4 MPa with an elongation of 22.5%. Grain refinement with LPSO formation simultaneously improved the strength and ductility of the ECAPed alloy, indicating a good plastic formability. The ECAPed Mg sheet was easily rolled at 773 K from 1.5 mm to 0.24 mm in thickness without edge cracking. After rolling, the fine-grained Mg alloy exhibited higher tensile strength with appropriate elongation. The post-ECAP rolling has been successfully used in the high productivity of Mg thin sheet with good mechanical properties.