(北京科技大學 鑄造研究所，北京 100083)
摘 要: 通過差示掃描量熱法確定半固態(tài)7075鋁合金溫度與固相分數的關系，采用Couette型同軸雙筒流變儀研究連續(xù)冷卻狀態(tài)下半固態(tài)7075鋁合金漿料的表觀黏度及其影響因素。結果表明：在連續(xù)冷卻條件下，當剪切速率( )不變時，冷卻速率(v)越大，半固態(tài)7075鋁合金漿料的表觀黏度(ηa)越大；當冷卻速率一定時，剪切速率越 大，相同溫度時半固態(tài)7075鋁合金漿料的表觀黏度越小。對半固態(tài)7075鋁合金漿料的表觀黏度與冷卻速率、剪切速率及固相分數(fs)的關系進行數值擬合，為半固態(tài)7075鋁合金成形的計算機模擬提供了依據：當剪切速率 =61.235 s-1時， ；當冷卻速率v=4 ℃/min時， 。
關鍵字: 7075鋁合金；半固態(tài)；連續(xù)冷卻；表觀黏度
（Institute of Foundry, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The apparent viscosity and its affecting factors of the semi-solid slurry of 7075 alloy were studied through a Couette-type viscometer during continuously cooling process. The differential scanning calorimetry (DSC) was performed to examine the solid fraction at different temperature. The results show that the apparent viscosity (ηa) of the slurry increases with the increase of cooling rate (v) when shearing rate ( ) is identical, while it decreases with the increase of shearing rate when cooling rate is identical. The empirical equation that shows the effect of cooling rate, solid fraction (fs) and shear rate on the apparent viscosity is fitted as follows: at =61.235 s-1, ; at v=4 ℃/min, . It provides a model for the simulation of semi-solid 7075 aluminum processing.
Key words: 7075 aluminum alloy; semi-solid; continuously cooling; apparent viscosity
