(北京有色金屬研究總院，北京 100088)
摘 要: 采用電磁攪拌連續(xù)鑄造裝置，制備具有觸變性非枝晶組織的半固態(tài)鋁合金圓棒。棒料內(nèi)部組織形貌為具有類圓形輪廓的初生相晶粒浸潤(rùn)在細(xì)共晶體中，與傳統(tǒng)的凝固枝晶組織有顯著差異。對(duì)半固態(tài)非枝晶組織的演化機(jī)理進(jìn)行了探討，結(jié)果表明處于交變電磁場(chǎng)中的金屬液體，可視為導(dǎo)電介質(zhì)流，它與磁場(chǎng)交互作用，在導(dǎo)電介質(zhì)流中產(chǎn)生徹體力。半固態(tài)非枝晶組織是在晶體正常的形核和長(zhǎng)大過(guò)程中，受徹體力強(qiáng)烈的混合抑制作用而形成的。
關(guān)鍵字: 連續(xù)鑄造；凝固組織；半固態(tài)合金；轉(zhuǎn)變機(jī)制
（General Research Institute for Nonferrous Metals, Beijing 100088, P.R.China）
Abstract:Experiments on semi-solid slurry forming were carried out by practical electromagnetic stirring-continuous casting method. Through optimizing the processing parameters, semi-solid Al-7%Si alloy cylinders with thixotropic non-dentritic structures were successfully produced. The diameter of the cylinder is in the range of 60～110mm. The original phase crystalline grains with roundish configuration are merged in fine eutetic-crystal, and this kind of microstructure is apparently different from conventional solidification crystal structure. The forming mechanism of the semi-solid rheological non-dentritic structures was discussed, the results show that the semi-solid non-dendritic structures are resulted from the strong restraint of normal crystal nucleation and growth in the semi-solid process.
Key words: continuous casting; solidification microstructure; semi-solid alloys; transform mechanism
