(1. 江西理工大學(xué) 機(jī)電工程學(xué)院，贛州 341000；
2. 江西理工大學(xué) 材料科學(xué)與工程學(xué)院，贛州 341000)
摘 要: 為獲得細(xì)小、圓整且分布均勻的半固態(tài)A356合金初生α相，向合金熔體中添加了不同含量的混合稀土La和Ce對(duì)合金進(jìn)行變質(zhì)處理，熔體經(jīng)620 ℃澆注后，利用變頻控制的電磁攪拌裝置對(duì)熔體進(jìn)行電磁攪拌15 s并使其在610 ℃保溫10 min，觀察并分析合金凝固組織中初生α相的形貌與尺寸。利用掃描電鏡和能譜儀分析測(cè)定La和Ce在基體的分布情況，探討混合稀土元素在電磁攪拌條件下對(duì)初生α相的細(xì)化機(jī)制。結(jié)果表明：La和Ce在電磁攪拌條件下易于均勻分布在初生α相周?chē)旌舷⊥猎豅a與Ce在短時(shí)弱電磁攪拌的條件下可以高效地細(xì)化半固態(tài)A356合金組織，稀土對(duì)半固態(tài)A356鋁合金的初生α相細(xì)化機(jī)制與稀土在鋁合金中產(chǎn)生的共晶反應(yīng)有關(guān)。
關(guān)鍵字: 混合稀土；半固態(tài)A356合金；電磁攪拌；初生α相；共晶反應(yīng)
（1. Faculty of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology,
Ganzhou 341000, China;
2. Faculty of Materials Science and Engineering, Jiangxi University of Science and Technology,
Ganzhou 341000, China）
Abstract:In order to obtain the fine, round and uniform distribution primary α phase in semisolid A356 alloy, the different amounts of mixed RE elements La and Ce were added into the alloy melt，and the melt was poured at 620 ℃ and slightly electromagnetically stirred for 15 s with an electromagnetic stirrer controlled by frequency conversion, then, it was isothermally held at 615 ℃ for 10 min. The morphology and size of the primary α phase were analyzed, and the distributions of La and Ce were researched by SEM and EDS. The refinement mechanism of mixed RE under electromagnetic stirring was discussed. The results indicate that RE elements La and Ce are easy to uniformly distribute around the primary α phase under electromagnetic stirring, and RE elements La and Ce can effectively refine the primary α phase under the condition of short and weak electromagnetic stirring. The refining mechanism of RE on the primary α phase in semisolid A356 alloy can be concerned with the eutectic reaction induced by RE in the alloy.
Key words: mixed rare earth; semisolid A356 alloy; electromagnetic stirring; primary α-Al phase; eutectic reaction
