Effect of ultrasound treatment on Cu-Zn alloys

The application of power ultrasound to liquid and solidifying alloys is known to allow the formation of a non-dendritic and fine microstructure suitable for semi-solid feedstock production. In literature several papers report results about low melting point alloys but very limited data are available on Cu-base alloys. The aim of this paper is, therefore, to evaluate the effect of ultrasonic waves applied to Cu alloys during solidification in order to obtain a globular microstructure. Metallographic analyses showed the effectiveness of this technique in breaking the forming dendrites, giving rise to an almost globular structure, suitable for being used in semi-solid processing. The differences in microstructure morphology and phases composition resulted to affect the corrosion resistance of the analysed samples, in particular the semi-solid ones showed improved performance as a consequence of the homogenizing effect induced by the ultrasound treatment.