快速凝固粉末冶金AZ91镁合金的组织性能

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1～5 μm, 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383.2 MPa, 屈服强度275.1 MPa。合金的析出相形貌主要为近球形, 大小为50～200 nm, 挤压态的析出相明显增多。

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

AZ91 magnesium alloy was prepared by rapid solidification and powder metallurgy technology with self-made equipment. Microstructures 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, AlMg_2Zn. The as-extruded alloy bars retained the equiaxed grain structure but had a large number of precipitated phases, β-Al_(12)Mg_(17) and AlMg_2Zn. 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.