Microstructure, mechanical properties and stretch formability of as-rolled Mg alloys with Zn and Er additions

The magnesium alloy has a unique advantage in 3C fields due to its high specific strength and excellent electromagnetic shielding characteristic. However, it is difficult to deform homogeneously because of hexagonal close-packed structure. In the present work, the microstructure, mechanical properties and stretch formability of magnesium alloy sheets with different alloying elements were investigated. It was indicated that a trace addition of Zn or/and Er made a key role in modifying texture, activating shear bands formation and precipitating nanoscale second phases, respectively, which resulted in an obvious improvement in both stretch formability and mechanical properties. The results suggested that the Mg–0.5 Zn–0.5 Er alloy sheet exhibited higher tensile strength along the rolling direction, i.e., yield strength of 180 MPa and ultimate tensile strength of 201 MPa, accompanying with superior Erichsen value of 7.0 mm at room temperature. The good performances of the sheet were ascribed to weakening basal texture intensity, formation of shear bands and precipitation of nanoscale W-phase(MgZnEr).