(華中科技大學(xué) 材料成形與模具技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，武漢 430074)
摘 要: 應(yīng)用消失模鑄造振動(dòng)壓力凝固成形技術(shù)制備了Al-7Si-0.8Mg-0.3Y(ASMY)合金。通過SEM、XRD、DSC和TEM等測(cè)試方法對(duì)其鑄態(tài)和T6組織進(jìn)行分析，研究其對(duì)力學(xué)性能的影響。結(jié)果表明：在ASMY合金鑄態(tài)組織的晶界處生成有少量Al3Y短棒狀顆粒相；在T6熱處理過程中，稀土Y或Al3Y阻礙Mg2Si相的析出和擴(kuò)散聚集，使析出相Mg2Si呈彌散分布；Mg2Si相與晶界穩(wěn)定相Al3Y對(duì)合金同時(shí)起到釘扎強(qiáng)化作用；采用消失模鑄造振動(dòng)壓力凝固技術(shù)后，鋁合金的孔隙率顯著降低，從1.1%降低0.18%；ASMY合金消失模鑄造振動(dòng)壓力凝固試樣T6態(tài)的抗拉強(qiáng)度達(dá)到308 MPa，比A356普通消失模試樣T6態(tài)的抗拉強(qiáng)度提高29%。
關(guān)鍵字: Al-Si-Mg-Y合金；消失模鑄造；振動(dòng)壓力；組織；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
