Simulation And Experiment Study On Wetting Behavior Of Al/C Interface Under Ultrasound Coupling

In the production of high quality pure aluminum and aluminum alloy,the ingot structure is usually controlled by grain refinement to obtain a high quality aluminum ingot.Al-Ti-C and Al-Ti-B are the most widely used refiners.Compared with Al-Ti-B,Al-Ti-C refiner has better refine performance.However,the wetting of Al/C interface and the synthesis of TiC become the technical problems in the preparation of Al-Ti-C alloy refiner.In this paper,the wetting and spreading behaviors of Al/C interface under ultrasonic wave were simulated.Based on the simulation results,the acoustic direct coupling method was used to explore the wetting and reaction behavior of Al/C interface under ultrasonic coupling.Combined with the equipment problems encountered in the experiment,completed the design of 20kHz ultrasonic vibration system,and its modal analysis.(1)Based on FLUENT fluid mechanics software,the wetting and spreading behavior of aluminum melt under ultrasonic wave was simulated.It was found that ultrasonic wave can accelerate the wetting and spreading speed of aluminum melt.After applying ultrasonic wave,the internal pressure of melt significantly increased,positive and negative pressure inside the melt appeared alternately,the pressure value changed sinusoidally over time.(2)The acoustic direct coupling method was used to investigate the wetting and reaction behavior of Al/C interface under ultrasonic wave.It was found that the structure near the Al/C interface was divided into three layers under the ultrasonic coupling:graphite layer,salt layer and aluminum matrix layer.The massive TiAl3 phase was distributed in the aluminum matrix and the salt layer.The Ti element in the salt layer lowered the surface energy of aluminum melt and ran out as a reactant for TiAl3 and TiC.TiC is granular,the particle size is about 0.5?m.The amount of TiC particles increased significantly after ultrasonic treatment was applied,and the agglomeration of TiC particles was improved.(3)The working principle of ultrasonic transducer system was introduced.According to the principles of dynamics and experimental requirements,the types and materials of the ultrasonic vibration system were selected.The structure dimensions of ultrasonic vibration system were calculated according to half-wavelength principle.The structure of the designed 20kHz ultrasonic vibration system was approximated and simplified,and the finite element model was established.Based on the ANSYS finite element software,the ultrasonic vibration system was modeled.It was found that the vibration mode of the ultrasonic vibration system was longitudinal vibration only when the frequency was 19783kHz,and the error of the frequency was only 1%,which met the design requirements.