(1. 哈爾濱工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，哈爾濱 150001；
2. 哈爾濱工業(yè)大學(xué) 機電工程學(xué)院，哈爾濱 150001)
摘 要: 借助重力鑄造和擠壓鑄造技術(shù)分別成形了AlSi7Mg鋁合金模擬構(gòu)件，利用拉伸試驗機、金相顯微鏡和掃描電鏡等手段研究了工藝參數(shù)對成形件組織與性能的影響規(guī)律。結(jié)果表明：與重力鑄件相比，擠壓鑄造件的抗拉強度、伸長率和屈服強度分別提高了41%、562%和0.5%，擠壓鑄造件的平均晶粒尺寸隨著澆注溫度、模具溫度和保壓時間的增加呈現(xiàn)出先減小后增大的趨勢。最佳擠壓鑄造工藝參數(shù)范圍為澆注溫度700~720 ℃、模具溫度200~250 ℃、保壓15~30 s，在該工藝條件下最好的綜合力學(xué)性能為抗拉強度221 MPa、屈服強度121.5 MPa和伸長率7.6%。Si、Fe、Mn、Mg等元素在晶界處發(fā)生偏析，對擠壓鑄造成形件的力學(xué)性能會產(chǎn)生不利影響。
關(guān)鍵字: AlSi7Mg鋁合金；擠壓鑄造; 微觀組織; 力學(xué)性能
（1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:AlSi7Mg aluminum alloy components were formed by gravity casting and squeeze casting. Influences of process parameters on microstructure and mechanical properties of formed parts were investigated by tensile test, optical microscopy and scanning electron microscopy. The results show that the yield strength, ultimate tensile strength and elongation of parts formed by squeeze casting increase by 41%, 562% and 0.5%, respectively, comparing with those of parts formed by gravity casting. The average grain size of parts formed by squeeze casting decreases and then increases with increases of pouring temperature, die temperature and dwell time. The optimal process parameters obtained in this research involve the pouring temperature range from 700 ℃ to 720 ℃, die temperature range from 200 ℃ to 250 ℃ and dwell times from 15 s to 30 s. The optimal mechanical properties such as yield strength of 121.5 MPa, ultimate tensile strength of 221 MPa and elongation of 7.6% are achieved under the optimal conditions. The alloy elements such as Si, Fe, Mn and Mg segregate on the grain boundary, which is detrimental to the mechanical properties of parts formed by squeeze casting.
Key words: AlSi7Mg aluminum alloy; squeeze casting; microstructure; mechanical properties
