(华中科技大学 材料成形与模具技术国家重点实验室，武汉 430074)
摘 要: 应用消失模铸造振动压力凝固成形技术制备了Al-7Si-0.8Mg-0.3Y(ASMY)合金。通过SEM、XRD、DSC和TEM等测试方法对其铸态和T6组织进行分析，研究其对力学性能的影响。结果表明：在ASMY合金铸态组织的晶界处生成有少量Al3Y短棒状颗粒相；在T6热处理过程中，稀土Y或Al3Y阻碍Mg2Si相的析出和扩散聚集，使析出相Mg2Si呈弥散分布；Mg2Si相与晶界稳定相Al3Y对合金同时起到钉扎强化作用；采用消失模铸造振动压力凝固技术后，铝合金的孔隙率显著降低，从1.1%降低0.18%；ASMY合金消失模铸造振动压力凝固试样T6态的抗拉强度达到308 MPa，比A356普通消失模试样T6态的抗拉强度提高29%。
关键字: Al-Si-Mg-Y合金；消失模铸造；振动压力；组织；性能
vibration-pressure solidification in lost form casting
（State Key Laboratory of Material Processing and Die and Mould Technology,
Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:Al-7Si-0.8Mg-0.3Y (ASMY) alloy was produced with vibration-pressure solidification in lost foam casting (LFC). The microstructure and mechanical properties of the as-cast and T6 heat treatment ASMY alloys were investigated by SEM, XRD, DSC and TEM. The results indicate that a small amount of short rod-like Al3Y particle generates at the grain boundary of the as-cast ASMY alloy. In the T6 heat treatment process, the rare-earth Y or Al3Y has a certain inhibition for the precipitation and aggregation of Mg2Si phase, which leads to the dispersive distribution of precipitated Mg2Si phase. Both Mg2Si phase and Al3Y stable phase in the grain boundary play an important role in pinning dislocations. The porosities of aluminium alloy by vibration-pressure solidification in LFC are reduced obviously from 1.1% to 0.18%. After T6 heat treatment, the ultimate tensile strength of ASMY alloy by vibration-pressure solidification in LFC reaches 308 MPa, and it is increased by 29% compared with that of A356 alloy by conventional LFC.
Key words: Al-Si-Mg-Y alloy; lost foam casting (LFC); vibration-pressure; microstructure; mechanical property
