In this work, the mechanical properties and failure characteristics of a Mg-9.0Al-0.8Zn alloy (AZ91) fabricated via the Thixomolding process (TC) were investigated and compared with those of alloys formed via other casting processes, including cold-chamber die-casting (CD) and hot-chamber die-casting (HD). The microstructure of the three cast samples mainly consisted of the α-Mg phase and eutectic Mg₁₇Al₁₂. Fine, uniformly organized spherical α-Mg grains formed in the TC sample, and this morphology can be related to the TC process. A relatively small microstructure, comparable to the TC sample, was also obtained with CD because of the high solidification rate. However, large grains and cast defects were observed in the HD sample. Shrinkage porosity cast defects were dominant with HD, and they were caused by the low casting pressure. The ultimate tensile strength and 0.2% proof stress of the TC sample were 279 MPa and 192 MPa, respectively, which was ~10% higher than for the CD sample. The cast defects and large grains for the HD sample caused a significant reduction in its tensile properties, although its 0.2% proof stress was relatively similar to the CD sample. High fatigue strength and high crack growth resistance were realized with TC. Failure analysis was also carried out to probe the excellent mechanical properties of the TC sample.

在这项工作中，研究了通过触变成型工艺（TC）制备的Mg-9.0Al-0.8Zn合金（AZ91）的力学性能和破坏特性，并将其与通过其他铸造工艺（包括冷室模头）形成的合金的力学性能和破坏特性进行了比较铸造（CD）和热室压铸（HD）。三个铸件的显微组织主要由α- Mg相和共晶Mg ₁₇ Al _12组成。精细，均匀组织的球形α-镁样品在TC样品中形成，这种形态可能与TC过程有关。由于高的固化速度，用CD也可获得与TC样品相当的相对较小的微观结构。然而，在HD样品中观察到大晶粒和铸件缺陷。缩孔率铸件缺陷主要是HD，这是由于铸造压力低引起的。TC样品的极限抗拉强度和0.2％屈服强度分别为279 MPa和192 MPa，比CD样品高约10％。HD样品的铸造缺陷和大晶粒导致其拉伸性能显着降低，尽管其0.2％屈服应力与CD样品相对相似。TC实现了高疲劳强度和高抗裂纹扩展性。