Influences of alloying element Zn on the microstructures and mechanical properties of GW series magnesium alloys

The influences of alloying element Zn on the microstructures and mechanical properties of GW magnesium alloys were investigated by using OM, XRD, SEM and mechanical property tests. The results show that the snow flake-like δ-Mg dendrites formed. Moreover, the morphology is still kept after annealing. The second phase changed from skeleton frame to net-shape with adding Zn. The ultimate tensile strength and the yield strength of the experimental alloys named GWZ721 reached 250 and 235 MPa respectively, and the elongation also reached 6.2%, which are much better than those of the experimental alloy named GW72 without adding Zn. The ultimate tensile strength and the yield strength of the alloys named GWZ721 at elevate room temperature decreased slightly with increasing the temperature, however, the elongation increased with increasing the temperature. The ultimate tensile strengths after heat-treatments at 200, 250 and 300°C still kept 225, 220 and 205 MPa, respectively.