(1. 宁波合力模具科技股份有限公司，宁波 315700；
2. 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: 采用挤压铸造方法探讨了高压强作用下Mg-6Zn-1.4Y-0.6Zr (ZW61)合金的凝固组织及性能变化。结果表明：当凝固压强从0 MPa逐渐增高至800 MPa时，ZW61合金组织被大幅度细化，缩松减少。随着挤压压强增大，平均晶粒尺寸及第二相准晶I相的体积分数不断减小。由于组织细化及零件的致密化，增高压强导致力学性能特别是伸长率显著提高。当挤压压强为800 MPa时，ZW61合金的铸态抗拉强度和伸长率分别为243 MPa和18.7%，比重力铸造时的分别提高35%和118%。
关键字: Mg-Zn-Y合金；高压；挤压铸造；组织；性能
（1. Ningbo Heli Mould Technology Co. Ltd., Ningbo 315700, China;
2. State Key Lab of Materials Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:The effects of high pressure on the solidification microstructure and mechanical properties of Mg-6Zn-1.4Y-0.6Zr (ZW61) alloy were investigated by squeeze casting method. The results indicate that a remarkable microstructure refinement and porosity reduction can be obtained through the application of high pressure up to 800 MPa during solidification. The average grain size and the volume fraction of second phase, i.e. quasicrystal I-phase, decrease continuously with the increase of applied pressure. Due to the microstructure refinement and castings densification, the increase of applied pressure leads to obvious enhancement of tensile properties, especially in elongation. When the applied pressure is 800 MPa, the ultimate tensile strength and elongation of ZW61 alloy in as-cast state are 243 MPa and 18.7%, increase by 35% and 118%, respectively, compared with those of the gravity-cast one.
Key words: Mg-Zn-Y alloy; high pressure; squeeze casting; microstructure; mechanical properties
