Ultrasound-Assisted Solidification of a Cu–Cr Alloy

Ultrasonic cavitation radiates huge power in a small solidifying bulk, leading to significant grain refinement, purification and homogenization of the final alloys. Ultrasound vibration has mostly been used for treating the solidification of light metals, but it is difficult to directly introduce ultrasonic vibration into copper alloy due to the lack of proper sonotrode. In this work, we have used a Sialon ceramic sonotrode to propagate acoustic waves in a Cu–Cr alloy melt. Significant grain refinement and modification of primary Cr have been obtained. With the ultrasound vibration treatment, the mechanical properties of the as-cast Cu–Cr alloy have been improved. The wear resistance of the Cu–Cr alloy has also shown enhancement with respect to the untreated alloy.