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采用挤压铸造工艺制备Mg-Zn-Y准晶增强AZ91D镁基复合材料,研究挤压压力对此复合材料显微组织和力学性能的影响。研究结果表明:挤压铸造工艺是细化晶粒的有效方法,复合材料由α-Mg基体、β-Mg17Al12相以及二十面体Mg3Zn6Y准晶相(I相)组成,且随着挤压压力的增大,β-Mg17Al12相以及Mg3Zn6Y准晶颗粒含量增加,基体晶粒进一步细化,α-Mg树枝晶向等轴晶转变;当挤压压力为100 MPa时,极限抗拉强度和断后伸长率达到最大值,分别为194.3 MPa和9.2%,拉伸断口出现大量韧窝;准晶增强AZ91D镁基复合材料的强化机制主要为细晶强化和准晶颗粒强化。
The squeeze casting process was used to prepare Mg-Zn-Y quasicrystal reinforced AZ91D magnesium matrix composites to study the effect of extrusion pressure on the microstructure and mechanical properties of the composites. The results show that the squeeze casting process is an effective method for grain refinement. The composites consist of α-Mg matrix, β-Mg17Al12 phase and icosahedral Mg3Zn6Y quasicrystal phase (I phase) , The content of β-Mg17Al12 phase and Mg3Zn6Y quasicrystalline particles increased, the matrix grains were further refined, and the transformation of α-Mg dendrites into equiaxed grains. When the extrusion pressure was 100 MPa, the ultimate tensile strength and elongation at break The maximum reached 194.3 MPa and 9.2%, respectively, and a large number of dimples appeared at the tensile fracture. The strengthening mechanism of the quasicrystal-reinforced AZ91D magnesium-based composite was mainly fine grain strengthening and quasicrystalline grain strengthening.