Development of high strength and ductility in Mg-2Zn extruded alloy by high content Mn-alloying

Mg-Zn-Mn alloys have drawing crucial attention because of the high strength, high ductility and excellent age harden ability. In the current work, we have systematically investigated the influence of Mn on the microstructure evolution and mechanical properties of as-extruded Mg-2Zn-Mn alloy. Results revealed that the mechanical properties that containing tensile and compressive strengths remarkably increased with high Mn content (2 wt%) addition. The dynamic recrystallized grains of Mg-2Zn alloy were significantly refined from 20 gm to 2 gm because of a mass of fine Mn precipitates effectively blocked newborn grain growth during extrusion process. The enhanced strengths were mainly ascribed to the high volume fraction of fine grains and the numerous fine precipitates. The strengthening mechanism and strain hardening behaviors of the alloys were also discussed.