半固態(tài)AlSi9Mg合金組織的影響
(1. 河北科技大學(xué) 材料科學(xué)與工程學(xué)院，石家莊 050018；
2. 中國南車集團(tuán)石家莊車輛廠，石家莊 050000)
摘 要: 利用自制的實驗裝置研究傾斜式冷卻剪切流變技術(shù)制備半固態(tài)AlSi9Mg合金。結(jié)果表明：合金熔體在傾斜冷卻板表面非均勻形核并受到重力和振動力的剪切作用，初生α(Al)逐漸從枝晶網(wǎng)絡(luò)演化為細(xì)小的球狀或粒狀晶；控制澆注溫度在600 ℃、傾斜板長度在600 mm、振動頻率在50 Hz時可以獲得組織良好的半固態(tài)合金熔體，合金熔體中初生α(Al)的平均晶粒尺寸為50 μm，形狀因子為0.71；機(jī)械振動能顯著細(xì)化AlSi9Mg合金組織，隨著振動頻率的提高，初生α(Al)明顯細(xì)化，圓整度也隨之提高。
關(guān)鍵字: AlSi9Mg合金；半固態(tài)；冷卻剪切；組織
（1.School of Material Science and Engineering, Hebei University of Science and Technology,
Shijiazhuang 050018, China;
2. CSR Shijiazhuang Rolling Stock Works, Shijiazhuang 050000, China）
Abstract: An experimental set-up of inclined cooling and shearing was developed to prepare semi-solid AlSi9Mg alloy. The results show that the molten alloy is nucleated heterogeneously on the inclined-cooling plate surface and under shearing of the gravitation and vibration. Original α(Al) phase converts gradually from the cellular dendrite into tiny spherical or granular crystal. Under pouring temperature of 600 ℃, sloping plate length of 600 mm and vibration frequency of 50 Hz, the semisolid alloy melt with good microstructure can be obtained. In the alloy melt the average grain size of the original α(Al) phase is 50 μm, and its shape factor is 0.71. Mechanical vibration can refine obviously the microstructure of AlSi9Mg alloy. With increasing vibration frequency, the original α(Al) phases are refined obviously, and their roundness is improved.
Key words: AlSi9Mg alloy; semisolid; cooling/shearing; microstructure
