**H. Puga 1,\*, J. Barbosa <sup>1</sup> and V. H. Carneiro <sup>2</sup>**


Received: 25 March 2019; Accepted: 25 April 2019; Published: 27 April 2019

**Abstract:** New alloy processes have been developed and casting techniques are continuously evolving. Such constant development implies a consequent development and optimization of melt processing and treatment. The present work proposes a method for studying the influence of acoustic pressure in the overall refinement of sand cast aluminum alloys, using and correlating experimental and numerical approaches. It is shown that the refinement/modification of the α-Al matrix is a consequence of the acoustic activation caused in the liquid metal directly below the face of the acoustic radiator. Near the feeder, there is a clear homogeneity in the morphology of the α-Al with respect to grain size and grain circularity. However, the damping of acoustic pressure as the melt is moved away from the feeder increases and the influence of ultrasound is reduced, even though the higher cooling rate seems to compensate for this effect.

**Keywords:** ultrasonic melt refinement; sand casting: acoustic radiator; α-Al grain size; aluminum alloy
