(上海大學(xué) 上海現(xiàn)代冶金與材料制備重點(diǎn)實(shí)驗(yàn)室，上海 200072)
摘 要: 研究旋轉(zhuǎn)磁場(chǎng)的勵(lì)磁電流和旋轉(zhuǎn)頻率對(duì)高硅鋁合金凝固組織的影響，并利用高速攝像機(jī)、SEM和EDS對(duì)高硅鋁合金中硅相及其他金屬間化合物形貌的演變進(jìn)行分析。結(jié)果表明，旋轉(zhuǎn)磁場(chǎng)可以抑制高硅鋁合金的宏觀偏析，細(xì)化初晶硅顆粒，形成類共晶組織；隨著勵(lì)磁電流和旋轉(zhuǎn)頻率的增大，初晶硅轉(zhuǎn)變方式為長(zhǎng)棒狀-塊狀-大塊塊狀團(tuán)簇，共晶硅轉(zhuǎn)變方式為長(zhǎng)針狀-蠕蟲狀-針狀；旋轉(zhuǎn)磁場(chǎng)還可以改善Al2Cu相和Al-Si-Fe相的形貌，使其依附甚至包覆在Si相周圍生長(zhǎng)，抑制合金熔體中Si相的長(zhǎng)大，有助于改善合金的力學(xué)性能。
關(guān)鍵字: 高硅鋁合金；旋轉(zhuǎn)磁場(chǎng)；勵(lì)磁電流；旋轉(zhuǎn)頻率；相組織
（Shanghai Key Laboratory of Modern Metallurgy and Material Processing, Shanghai University, Shanghai 200072, China）
Abstract:The influence of excitation current and rotational frequency on the solidification microstructure of high-silicon aluminum alloys was studied. The morphology evolution of Si and other intermetallic compounds was analyzed by using high speed camera, SEM and EDS. The results show that the rotating magnetic field(RMF) can suppress the macrosegregation in solidified high-silicon aluminum alloys, refine the primary Si particles and finally provide a eutectic-like structure. The morphology of primary Si phase changes from long rod to block, and then to large block clusters when both the excitation current and rotational frequency of RMF increase, meanwhile, the eutectic Si phase changes from long needle to wormlike particles, and then to needlelike particles. Moreover, RMF can improve the morphologies of Al2Cu and Al-Si-Fe phases, and the refined Al2Cu and Al-Si-Fe phases are attached around Si phase, which further refines the microstructure of the high-silicon aluminum alloys.
Key words: high-silicon aluminum alloy; rotating magnetic field; excitation current; rotational frequency; phase structure
