合金化元素Zn对GW系镁合金组织和力学性能的影响

INFLUENCES OF ALLOYING ELEMENT Zn ON THE MICROSTRUCTURES AND MECHANICAL PROPERTIES OF GW SERIES MAGNESIUM ALLOYS

通过OM、XRD、SEM等分析方法及拉伸实验研究了合金化元素Zn对GW系镁合金铸造组织和力学性能的影响.研究结果表明:加入合金化元素Zn后,合金组织发生较大变化,形成雪花状的δ-Mg枝晶,第二相由骨骼状变为相互连结的网状;而且在固溶处理以及时效处理过程中,二者形貌没有变化.实验合金GWZ721热处理唇室温的抗拉强度达到250 MPa,屈服强度达到235 MPa,延伸率达到6.2%,显著优于实验合金GW72.热处理后的高温瞬时抗拉强度和屈服强度随着温度的升高均略有下降,延伸率有所上升.在200,250和300℃时,实验合金的抗拉强度仍分别保持为225,220和205 MPa.

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 5-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 ℃ still kept 225, 220 and 205 MPa, respectively.