(華中科技大學(xué) 材料成形及模具技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，武漢 430074)
摘 要: 研究超聲振動(dòng)制備過(guò)共晶Al-Si合金半固態(tài)漿料中工藝參數(shù)對(duì)半固態(tài)漿料組織的影響規(guī)律。利用A390鋁合金熔體，超聲振動(dòng)至液固相線溫度區(qū)內(nèi)制漿，研究超聲振動(dòng)時(shí)間、振動(dòng)后保溫及空振比等不同條件下半固態(tài)漿料的組織變化。結(jié)果表明：超聲振動(dòng)后初晶Si可細(xì)化到20 µm左右；漿料在保溫過(guò)程中，初晶Si粒以8 µm/min的平均速度快速長(zhǎng)大，2 min內(nèi)初生Si晶粒仍保持較好的圓整度；2 min后初生Si晶粒慢慢惡化；在1℃/min的冷卻速度下，在0.5~10 min的振動(dòng)時(shí)間范圍內(nèi)，初生Si以小于2.5 µm/min的速度緩慢長(zhǎng)大；當(dāng)超聲振動(dòng)的空振比為0.5時(shí)，初生晶粒的細(xì)化效果最好。
關(guān)鍵字: Al-Si合金；超聲振動(dòng)；過(guò)共晶；半固態(tài)漿料；空振比
（State Key Laboratory of Material Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:The effects of process parameters on microstructures of hypereutectic Al-Si semi-solid slurry were investigated. The A390 melt was imposed with ultrasonic vibration once it was poured into the metal cup and controlled in the liquid-solid temperature range, and the effects of ultrasonic vibration time, isothermal holding time, rest-work ratio on the semisolid slurry were studied. The results show that the primary Si phase is refined to about 20 µm. And with the increase of the isothermal holding time after ultrasonic vibration period, the primary Si particles grow up rapidly at the velocity of 8 µm/min, and the primary Si particles remain globular in 2 min while the morphologies deteriorate after 2 min. The primary Si particles grow slowly at the speed below 2.5 µm/min with relative stable morphology under ultrasonic vibration within 0.5−10 min. Ultrasonic vibration with rest-work ratio of 0.5 other than continuous ultrasonic vibration achieves the best refinement result.
Key words: Al-Si alloy; ultrasonic vibration; hypereutectic; semisolid slurry; rest-work ratio
