快速凝固粉末冶金AZ91镁合金的组织性能

Microstructures and Mechanical Properties of AZ91 Mg Alloy Processed by Rapid Solidification and Powder Metallurgy Technology

采用自制的设备，用快速凝固粉末冶金方法制备了AZ91镁合金，分别对合金进行光学金相、XRD、HRTEM、SEM分析。结果表明：粉末态为非常均匀细小的等轴晶组织，晶粒大小为1～5μm，只有很少析出相，析出相为AlMg2Zn。挤压棒材为细小的等轴晶组织，有大量的析出相，主要为β—Al12Mg17和AlMg2Zn。合金有很高的力学性能，抗拉强度达到383．2MPa，屈服强度275．1MPa。合金的析出相形貌主要为近球形，大小为50～200nm，挤压态的析出相明显增多。

AZ91 magnesium alloy was prepared by rapid solidification and powder metallurgy technology with self-made equipment. Mierostruetures of the alloy materials were observed by optical microscope （OM）, XRD, HRTEM and SEM. The results showed that the powders had a uniform, fine, equiaxed grain structure with a grain size of 1 - 5 μm and only a few precipitated phases, AlMg2Zn. The as-extruded alloy bars retained the equiaxed grain structure but had a large number of precipitated phases, β-Al12Mg17 and AlMg2Zn. The alloy exhibited excellent mechanical properties. The tensile strength and yield strength were 383.2 MPa and 275.1 MPa respectively. The precipitated phases were mostly subsphaeroidal, about 50 -200 nm in size, and obviously increased in the extruded material.