(1. 江西理工大學 機電工程學院，贛州 341000； 2. 江西理工大學 材料科學與工程學院，贛州 341000)
摘 要: 采用自行設(shè)計的電磁調(diào)控裝置對結(jié)晶器內(nèi)的鋁熔體施加雙向電磁攪拌處理，獲得凝固組織為球狀或類球狀初生固相顆粒的半固態(tài)漿料，分析在電磁攪拌時間恒定12 s時磁場頻率、電磁攪拌方式(單向連續(xù)電磁攪拌、雙向連續(xù)電磁攪拌、雙向間歇電磁攪拌)對初生相形貌演化的影響。結(jié)果表明：隨著磁場頻率的增加，初生固相晶粒的生長形態(tài)由樹枝狀、長條狀、粗顆粒狀轉(zhuǎn)變?yōu)榍驙睿痪Я３叽缦葴p小后增大；磁場頻率存在最佳值30 Hz 。此時，初生相α(Al)的平均等積圓直徑為38.2 μm，形狀因子為0.75。此外，雙向連續(xù)電磁攪拌作用于液態(tài)熔體形成強烈的紊流和慣性沖擊，加快凝固體系的質(zhì)量傳輸熱量傳遞，合金漿料組織相較于單向連續(xù)電磁攪拌、雙向間歇電磁攪拌更加細小圓整。
關(guān)鍵字: 半固態(tài)；A356鋁合金；雙向電磁攪拌；凝固組織
（1. School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China; 2. School of Materials Science and Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China）
Abstract:A semi-solid slurry with solidified structure of spherical or spheroid primary solid particles was obtained by using a self-designed electromagnetic control device to two-way electromagnetic stirring the aluminum melt in the mold. The influences of magnetic field frequency and electromagnetic stirring ways (single way continuous electromagnetic stirring, two-way continuous electromagnetic stirring, two-way intermittent electromagnetic stirring) on the morphological evolution of the primary phase were analyzed when the electromagnetic stirring time was constant at 12s. The results show that, with the increase of the magnetic field frequency, the morphologies of primary solid phase grains change from dendritic, long strip, coarse granular to spherical shape, the grain size first decreases and then increases, the optimum magnetic field frequency is 30 Hz. In this case, the average equal-area circle diameter of primary α(Al) is 38.2 μm, and the average shape factor is 0.75. In addition, when two-way continuous electromagnetic stirring are applied on the liquid melt to form strong turbulence and inertial impact, the mass transfer and heat transfer of the solidified system are accelerated. The slurry structure of alloy is more compact and rounded than those by the single-way continuous electromagnetic stirring and two-way intermittent electromagnetic stirring.
Key words: semisolid; A356 aluminum; two-way electromagnetic stirring; solidification microstructure
