(東北大學(xué) 材料電磁過程研究教育部重點實驗室，沈陽 110819)
摘 要: 采用超聲駐波處理Al-20%Si合金熔體，研究不同超聲駐波處理功率下Al-20%Si合金的微觀組織演變，探討超聲駐波對Al-20%Si合金凝固過程的作用和組織細化的機理。結(jié)果表明：超聲駐波能抑制初晶硅的析出，但聲輻射力的作用使已析出的初晶硅偏聚長大；超聲駐波處理能實現(xiàn)共晶硅“片狀-纖維狀”明顯的形態(tài)轉(zhuǎn)變，凝固后共晶硅轉(zhuǎn)變?yōu)轭l繁分支細小的纖維狀；超聲功率越大，共晶硅“片狀-纖維狀”的形態(tài)轉(zhuǎn)變越明顯；超聲駐波可以用于亞共晶Al-Si合金的變質(zhì)處理中。
關(guān)鍵字: Al-20%Si合金；超聲駐波；微觀組織演變
（Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education,
Northeastern University, Shenyang 110819, China）
Abstract:A hypereutectic Al-20%Si alloy was treated by ultrasonic standing wave and the microstructure evolution of Al-20%Si alloy was studied under different ultrasonic powers. The course of crystallization and mechanism of microstructural refinement for the ultrasonic treated alloy were also discussed. The results show that the precipitation of primary silicon is inhibited while the segregation and growth of primary silicon are promoted because of acoustic radiation force under the ultrasonic standing waves treatment. The morphology of eutectic Si is obviously changed after ultrasonic standing wave treatment, varying from flake to fiber shape. Eutectic Si is changed into fine fiber shape with many branches. With the increase of ultrasonic power, the morphological change of eutectic Si from flake to fiber shape is more obvious. Ultrasonic standing wave can be used in the modification of hypoeutectic Al-Si alloy.
Key words: Al-20%Si alloy; ultrasonic standing wave; microstructure evolution
