(1. 湖南大學(xué) 汽車車身先進(jìn)設(shè)計(jì)與制造國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410082；
2. 湖南大學(xué) 機(jī)械與運(yùn)載工程學(xué)院，長(zhǎng)沙 410082；
3. 中南林業(yè)科技大學(xué) 機(jī)電工程學(xué)院，長(zhǎng)沙 410004)
摘 要: 采用旋轉(zhuǎn)黏度計(jì)測(cè)定AlSi10MnMg鋁合金熔體的黏度，壓鑄制備薄壁鋁合金鑄件，并用高速攝像技術(shù)記錄分析充型速度，計(jì)算流體力學(xué)參數(shù)Re數(shù)和We數(shù)來表征薄壁鋁合金壓鑄充型過程中的流動(dòng)特征，最后采用OM研究其組織。結(jié)果表明：旋轉(zhuǎn)黏度計(jì)適合于測(cè)定非牛頓流體鋁合金熔體系統(tǒng)；鋁合金熔體以層流、充型前端液面自由表面破碎成細(xì)小液滴的形式高速填充薄壁流動(dòng)試樣型腔；澆注溫度升高，黏度減小，充型時(shí)間、充型速度和充型距離增加，氣孔增加，α(Al)晶粒由塊狀向球狀、薔薇狀轉(zhuǎn)變，晶粒尺寸分布越來越均勻；沿充型流動(dòng)長(zhǎng)度方向，氣孔先增加后減少，晶粒尺寸分布變化不大；鑄件中心位置晶粒尺寸、α(Al)相含量大于型壁邊界位置。
關(guān)鍵字: 薄壁鋁合金；高溫壓鑄；流動(dòng)特征；凝固組織；充型過程
（1. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,
Hunan University, Changsha 410082, China
2. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
3. College of Mechanical and Electrical Engineering,
Central South University of Forestry and Technology, Changsha 410004, China）
Abstract:The viscosity of AlSi10MnMg aluminum alloy was measured by a rotational viscometer. The thin-wall fluidity samples were prepared by high pressure die casting. The filling velocity was recorded and analyzed by high speed camera system. Re and We were calculated to represent the flow characteristics during the filling process. OM was employed to study the microstructure. The results show that the rotational viscometer is suitable for the non-Newtonian fluid aluminum alloy melt system. The aluminum alloy melt fills the cavity of thin-wall fluidity specimen at a high-speed in the form of laminar flow when the melt free surface is broken into small droplets. While the viscosity decreases with the pouring temperature increasing, the filling fluidity time, velocity and length increase. High temperature increases porosity and causes that the morphology of α(Al) grain changes from massive to spherical and rose-shaped. The grains become uniform with the temperature increasing. The porosity decreases firstly and then increases, but the change of grain size distribution is undetectable along fluidity length. Both the grain size and α(Al) phase in the center are higher than those in the boundary.
Key words: thin-wall aluminum alloy; high pressure die casting; flow characteristics; solidified microstructure; filling process
