中国有色金属学报
中國有色金屬學報
중국유색금속학보
THE CHINESE JOURNAL OF NONFERROUS METALS
2014年
1期
43-52
,共10页
朱必武%李落星%刘筱%张立强%卜晓兵%徐戎
硃必武%李落星%劉篠%張立彊%蔔曉兵%徐戎
주필무%리락성%류소%장립강%복효병%서융
薄壁铝合金%高温压铸%流动特征%凝固组织%充型过程
薄壁鋁閤金%高溫壓鑄%流動特徵%凝固組織%充型過程
박벽려합금%고온압주%류동특정%응고조직%충형과정
thin-wall aluminum alloy%high pressure die casting%flow characteristics%solidified microstructure%filling process
采用旋转黏度计测定AlSi10MnMg铝合金熔体的黏度,压铸制备薄壁铝合金铸件,并用高速摄像技术记录分析充型速度,计算流体力学参数Re数和We数来表征薄壁铝合金压铸充型过程中的流动特征,最后采用OM研究其组织。结果表明:旋转黏度计适合于测定非牛顿流体铝合金熔体系统;铝合金熔体以层流、充型前端液面自由表面破碎成细小液滴的形式高速填充薄壁流动试样型腔;浇注温度升高,黏度减小,充型时间、充型速度和充型距离增加,气孔增加,α(Al)晶粒由块状向球状、蔷薇状转变,晶粒尺寸分布越来越均匀;沿充型流动长度方向,气孔先增加后减少,晶粒尺寸分布变化不大;铸件中心位置晶粒尺寸、α(Al)相含量大于型壁边界位置。
採用鏇轉黏度計測定AlSi10MnMg鋁閤金鎔體的黏度,壓鑄製備薄壁鋁閤金鑄件,併用高速攝像技術記錄分析充型速度,計算流體力學參數Re數和We數來錶徵薄壁鋁閤金壓鑄充型過程中的流動特徵,最後採用OM研究其組織。結果錶明:鏇轉黏度計適閤于測定非牛頓流體鋁閤金鎔體繫統;鋁閤金鎔體以層流、充型前耑液麵自由錶麵破碎成細小液滴的形式高速填充薄壁流動試樣型腔;澆註溫度升高,黏度減小,充型時間、充型速度和充型距離增加,氣孔增加,α(Al)晶粒由塊狀嚮毬狀、薔薇狀轉變,晶粒呎吋分佈越來越均勻;沿充型流動長度方嚮,氣孔先增加後減少,晶粒呎吋分佈變化不大;鑄件中心位置晶粒呎吋、α(Al)相含量大于型壁邊界位置。
채용선전점도계측정AlSi10MnMg려합금용체적점도,압주제비박벽려합금주건,병용고속섭상기술기록분석충형속도,계산류체역학삼수Re수화We수래표정박벽려합금압주충형과정중적류동특정,최후채용OM연구기조직。결과표명:선전점도계괄합우측정비우돈류체려합금용체계통;려합금용체이층류、충형전단액면자유표면파쇄성세소액적적형식고속전충박벽류동시양형강;요주온도승고,점도감소,충형시간、충형속도화충형거리증가,기공증가,α(Al)정립유괴상향구상、장미상전변,정립척촌분포월래월균균;연충형류동장도방향,기공선증가후감소,정립척촌분포변화불대;주건중심위치정립척촌、α(Al)상함량대우형벽변계위치。
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 ofα(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 andα(Al) phase in the center are higher than those in the boundary.