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研究了27.5 kHz高频超声振动下SCN-3%ETH(Succinonitrile-3%ethanol,质量分数)模拟合金的定向凝固过程.结果表明,超声作用时界面出现钝化,曲率半径随超声作用时间的增加不断增大;撤去超声振动后,界面上形成被细化的胞晶组织;由于空化效应产生的瞬时高温高压的冲击破坏和声流的搅拌作用以及强迫振动的剪切作用,部分枝晶尖端断裂;界面生长速度随超声作用时间的增加不断减小,超声振动在熔体中引起的空化效应和高频强迫振动是界面生长速度变化的主要原因.
The directional solidification process of SCN-3% ETH (Succinonitrile-3% ethanol) simulated alloy under 27.5 kHz high-frequency ultrasonic vibration was studied.The results show that the interface is passivated by ultrasonic and the radius of curvature increases with the increase of ultrasonic action time After the removal of ultrasonic vibration, the interface is formed of refined cellular crystal structure; due to the cavitation effect of transient high temperature and high pressure impact damage and mixing of acoustic flow and forced vibration of the shear effect, some dendrite tip The interfacial growth rate decreases with the increase of ultrasonic action time. The cavitation effect caused by ultrasonic vibration in melt and the high-frequency forced vibration are the main reasons for the change of interfacial growth rate.