(東北大學 理學院，沈陽 110004)
摘 要: 采用近液相線半連續(xù)鑄造技術(shù)制備A390合金坯料，對鑄錠顯微組織進行金相觀察，采用圖像分析軟件Image-Pro Plus計算晶粒尺寸，研究澆注溫度從高于液相線(650 ℃)100 ℃至10 ℃范圍內(nèi)變化對A390合金初生硅尺寸形貌的影響。結(jié)果表明：近液相線半連續(xù)鑄造時，較低的澆注溫度以及較均勻的溫度場有利于均勻形核，同時減小熔體中Si的濃度梯度，從而消除Si原子聚集成團的條件，抑制初生硅的生長；因此，僅控制近液相線半連續(xù)鑄造的工藝參數(shù)即可改善A390合金半固態(tài)坯料中初生硅尺寸形貌，這是制備過共晶鋁硅合金半固態(tài)坯料的簡單、可行、高效和低成本的方法。
關(guān)鍵字: A390合金；初生硅；半固態(tài)成形；近液相線半連續(xù)鑄造
A390 alloy during near-liquidus semi-continuous casting
（School of Sciences, Northeastern University, Shenyang 110004, China）
Abstract:The A390 alloy billets were prepared using the near-liquidus semi-continuous casting technology. The microstructures of billets were observed by metalloscopy. The grain size was calculated by the Image-Pro Plus software. The influence of pouring temperature from 100 ℃ to 10 ℃ above the liquidus (650 ℃) on the shape and size of primary silicon particles of A390 alloy were studied. The results show that lower temperature and more uniformly distributing temperature field in the melt during near-liquidus semi-continuous casting help to nucleation and decrease concentration gradient of Si, which eliminates the gathering process of Si atoms and restrains the anisotropic growth of primary Si particle. So, controlling the processing parameters of near-liquidus semi-continuous casting can improve the primary Si of A390 alloy semi-solid billets, which will be a simple, feasible and effective method to prepare the semi-solid billets of hypereutectic Al-Si alloys.
Key words: A390 alloy; primary Si; semi-solid forming; near-liquidus semi-continuous casting
