Coupling Effect of Adding Al-Ti-C Grain Refiner and Introducing Ultrasound to Molten Melt on the Microstructure of 7050 Aluminum Alloy

Ultrasound was introduced into 7050 aluminum alloy added Al-Ti-C grain refiners with different mass fractions. Influences of three methods of treating molten melt: applying single ultrasound, single Al-Ti-C grain refiners and the two together, on nucleation in the solidification process were studied through the analysis of the microstructures. The results show the cavitation effect caused by ultrasonic vibration changes the microstructure of Al-Ti-C grain refiners, increases the diffusion and wettability of the TiC clusters, restrains and smashes the growth of TiAl3 clusters, and then enhances the refinement effect of Al-Ti-C grain refiner. Therefore, when the melt was treated synchronously by ultrasound and grain refiner, the finer grains can be obtained than that by a single way.