超声空化对7050铝合金的细晶分析

7050铝合金半连续铸造过程中施加一定功率的超声,晶粒细化较为明显。从结晶热力学和动力学两方面,运用理论计算结合试验分析了超声振动在熔体中引起的空化泡共振机理,发现超声的空化效应能显著增大晶核的振动能量,从而显著增大晶核振动频率,引起晶粒的细化。定量研究了空化效应对7050铝合金铸造凝固过程中能量的传递及晶核振动频率的变化。探讨了超声在铝合金熔体中传播时空化泡的频率及其初始平衡半径对晶核振动频率及其形核规律的影响。

Effects of Ultrasonic Cavitation Behavior on Grain Refinement of 7050 Aluminum Alloy

Grain size in the semi-continuous casting 7050 aluminum alloy could be refined significantly with imposing ultrasonic power.Cavitation bubble co-vibrating mechanism in the aluminum alloy melt was analyzed by theoretical calculation and experiment based on crystallization thermo-dynamics and kinetics.The results reveal that cavitation effects can greatly increase the vibrating energy of grain nuclei,which is responsible for the refinement of grain size as a result of apparently increase the vibrating frequency of the nuclei.The effect of cavitation is quantitatively analyzed for energy transfer and change of vibrating frequency of the nuclei in 7050 aluminum alloy during semi-continuous casting process.In addition,effects of frequency of cavitation bubble and its initial equilibrium radius on nuclei vibrating frequency and nucleation in aluminum alloy melt with ultrasonic treatment were approached.