Study on Microstructure and Properties of Single‐Pass Online Heating Rolling of Mn‐Containing Magnesium Alloy Sheets

Mg–2.0Zn–1.5Mn (ZM21) alloy and Mg–1.0Mn–0.5Al (MA10) alloy extruded bars have excellent mechanical properties and low processing cost. Herein, these two alloys sheets are rolled at different temperatures and reductions by online heating rolling. In addition, their mechanical properties and microstructure characteristics are also studied through electron backscattered diffraction. The results show that the yield strength of rolled ZM21 sheets is gradually improved with increasing rolling strain and temperature and further exhibits good comprehensive mechanical properties. The mechanical properties of ZM21 rolled sheets are slightly lower than that of AZ31 rolled sheet and have the potential to substitute the AZ31 sheet. However, MA10 alloy rolled sheet herein exhibits poor mechanical properties, indicating that the mechanical properties of MA10 alloy highly depend on the microstructures resulting from the processing parameters. The mechanism of poor mechanical properties and different mechanical behaviors of extruded bars and extruded sheets are discussed. The mechanical properties of rolled ZM21 alloy sheets are slightly lower than rolled AZ31 alloy sheets after online heating rolling, while the MA10 alloy sheets have the worst mechanical properties compared with ZM21 and AZ31 sheets. In addition, it is found that the mechanical properties of extruded sheets are lower than that of extruded bars in MA10 alloy.