热处理对ZW21镁合金组织及性能的影响

Effects of Heat Treatment on Microstructure and Mechanical Properties of ZW21 Magnesium Alloy

采用金相显微镜、扫描电镜、X射线衍射仪及WDW-100D型电子万能实验机等对ZW21镁合金铸态及固溶+时效态的显微组织和力学性能进行了观察与分析。结果表明,经525℃固溶4h后进行250℃时效,合金中没有完全溶解的第二相将会随着时效时间的延长逐渐向晶内聚集,最后在晶粒内形成菊花状组织,并且经时效24h后,合金的抗拉强度达到最大243MPa,伸长率达23.75%,硬度(HV)达68.7,与铸态下的ZW21镁合金相比,其综合力学性能得到了显著提高。

Microstructure and mechanical properties of as-cast and solid solution-aged ZW21 magnesium alloy were investigated by OM (optical microscope), SEM (scanning electron microscope), XRD (X-ray diffraction) and WDW-100D electronic universal materials testing machine. The results indicate that the alloy with aging at 250℃ after solid solution at 525 ℃ for 4 hours, with extending aging time, the secondary phase which is not completely dissolved into the alloy, can gradually be gathered into the crystal to form the rosette-like structure. Moreover, with aging for 24 hours, tensile strength and elongation of the alloys reach 243 MPa and 23.75%, respectively, greatly superior to those of as-cast ZW21 magnesium alloy.