Effect of Ultrasonic Vibration on Microstructure and Mechanical Properties of Nano-SiC_p/Al-5Cu Composites

The ultrasonic vibration (UV) treatment has been successfully applied to improve the particles distribution of nano-SiCp reinforced Al-5Cu composites fabricated by combined processes of dry high energy ball milling and squeeze casting. Large particles aggregates are eliminated by effects of the cavitation and the acoustic streaming of UV for 1 min. All the particles aggregates are eliminated and the particles are uniformly distributed in the melt after treated by UV for 5 min. The ultimate tensile strength, yield strength and elongation of the 1%(mass fraction) nano-sized SiCp/Al-5Cu composites treated by UV for 5 min are 270 MPa, 173 MPa and 13.3%, which are increased by 7.6%, 6.8% and 29% compared with Al-5Cu matrix alloy, respectively, and are increased by 27.4%, 9.5% and 303% compared with the untreated composites, respectively. The improvements of mechanical properties after UV are attributed to the uniform distribution of reinforcement and grain refinement of aluminum alloy matrix