振动冷却斜管处理工艺对A357合金凝固组织的影响

Effects of Vibrating the Cooling Pipe on the Solidification Microstructure of A357 Alloy

采用振动冷却斜管的方法,研究了不同振动工艺参数及浇注温度条件下A357合金凝固组织中初生相及共晶组织的形态差异。结果表明:同一浇注温度下,提高振动加速度或提高振动频率有助于A357合金凝固组织中初生相的细化和球化;同时,在给定的频率条件下,随着振动加速度的提升,共晶Si相的形态趋于细化;较低的浇注温度有利于保存振动冷却斜管方法激发的晶核,从而强化A357合金凝固组织的细化效果。

Mechanical vibration is applied to A357 alloy during the pouring process through a cooling pipe and the solidification microstructure of the alloy is investigated. The results show that primary aluminum and eutectic silicon morphology were strongly influenced by the level of vibration frequency and vibration acceleration. Increasing in the vibration frequency or the vibration acceleration enhances the fineness and the spheroidicity of the primary aluminum morphology, which in sequence enhances the fineness of eutectic silicon phase. It is also found that decreasing in the pouring temperature improves the retention ratio of the chilling nucleus thus can enhance the grain refining effect in the solidification microstructure.