超声振动对SCN-3%ETH模拟合金定向凝固的影响

来源期刊：金属学报2010年第7期

论文作者：段萌萌 陈长乐

文章页码：885 - 889

关键词：超声振动； 定向凝固； 枝晶； 曲率半径

Key words：ultrasonic vibration； directional solidification； dendrite； the radius of curvature

摘    要：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.

Abstract: The directional solidification process of SCN-3%ETH model alloy under 27.5 kHz ultrasonic vibration is studied in this paper.The results show that the interface growth is restrained because of the effect of ultrasonic vibration.The radius of curvature on the interface increases as the ultrasonic action time increase.When the ultrasonic vibration is removed from the melt,the refined cellular structure is formed.Because the impact of transient high temperature and pressure generated by the cavitation effect and stirring action of the acoustic streaming and shearing action caused by forced vibration,part of the dendrite tips are fractured.The interface growth rate decreases as the ultrasonic action time increase.Cavitation effects and high-frequency forced vibration caused by ultrasonic vibration in the melt are main reasons for interface growth rate change.