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研究了添加稀土元素的不同高铝含量的变形挤压态镁合金的微观组织和力学性能。结果表明,铝含量的增加,挤压合金晶粒的得到了明显的细化,平均晶粒尺寸为(12±4)μm。挤压态合金的显微硬度高于固溶态合金的显微硬度;随着铝含量的增加,合金的时效硬化行为得到明显的改善。这些主要是由于在挤压过程中晶粒的细化和沿着挤压方向第二相的析出。另外,随着铝含量的增加,合金的屈服强度和抗拉强度也有所提高,分别达到了306和348 MPa。这主要取决于晶粒的进一步细化和析出相体积分数的增加。因镁稀土相和β-Mg17Al12相都为脆性相,铝含量的增加引起析出相体积分数的增加,也同时导致合金的伸长率有所下降。
The microstructure and mechanical properties of deformed magnesium alloy with different high contents of aluminum added with rare earth elements were studied. The results show that with the increase of aluminum content, the grain size of extruded alloy is obviously refined with the average grain size of (12 ± 4) μm. The microhardness of the extruded alloy is higher than that of the solid solution alloy. With the increase of aluminum content, the age hardening behavior of the alloy is obviously improved. These are mainly due to the grain refinement during extrusion and the precipitation of the second phase along the direction of extrusion. In addition, as the aluminum content increases, the yield strength and tensile strength of the alloy also increased, reaching 306 and 348 MPa. This mainly depends on the further refinement of the grains and the increase of the volume fraction of precipitated phase. Due to the brittle phase of the rare earth phase and the β-Mg17Al12 phase, the increase of the aluminum content causes the increase of the volume fraction of the precipitated phase, and also leads to the decrease of the elongation of the alloy.