(1. 寧波合力模具科技股份有限公司，寧波 315700；
2. 華中科技大學(xué) 材料成形與模具技術(shù)國家重點(diǎn)實(shí)驗(yàn)室，武漢 430074)
摘 要: 采用擠壓鑄造方法探討了高壓強(qiáng)作用下Mg-6Zn-1.4Y-0.6Zr (ZW61)合金的凝固組織及性能變化。結(jié)果表明：當(dāng)凝固壓強(qiáng)從0 MPa逐漸增高至800 MPa時，ZW61合金組織被大幅度細(xì)化，縮松減少。隨著擠壓壓強(qiáng)增大，平均晶粒尺寸及第二相準(zhǔn)晶I相的體積分?jǐn)?shù)不斷減小。由于組織細(xì)化及零件的致密化，增高壓強(qiáng)導(dǎo)致力學(xué)性能特別是伸長率顯著提高。當(dāng)擠壓壓強(qiáng)為800 MPa時，ZW61合金的鑄態(tài)抗拉強(qiáng)度和伸長率分別為243 MPa和18.7%，比重力鑄造時的分別提高35%和118%。
關(guān)鍵字: Mg-Zn-Y合金；高壓；擠壓鑄造；組織；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
