Study on the preparation of Al–Si functionally graded materials using power ultrasonic field

A novel approach was developed to prepare Al–Si functionally graded materials (FGM) using power ultrasonic field and water–cooling system. The distribution of primary Si of the FGM sample continuously decreased from outer to inner. The structure of the sample continuously changed from hypereutectic with a great number of primary Si to eutectic and then to hypoeutectic with numerous primary Al dendrites in well accordance with the distribution of primary Si. The hardness and wear resistance performances were characterized using HVS-5 Vickers hardness tester and UMT-2 multifunctional friction and wear tester. The results showed that these performances also had graded distribution. In addition, the co-effect of power ultrasonic field and water–cooling on the preparation of Al–Si FGM was discussed.