Zinc matrix composites prepared by ultrasonic assisted casting method
(1.College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China2.College of Materials Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
Abstract: By ultrasonic assisted casting method SiCp/ZA27 composites with particle diameter of 0.520μm, and volume fraction of 2%8% were prepared. The composites microstructure, effects of particles size and volume fraction on the composites properties and the function mechanism of high intensity ultrasonic in the melt were studied. The SiC particulates are uniform macro-distribution in the matrix. The TEM results show that the interface between SiCp/ZA27 is planar without reaction products and precipitations, and there are lots of dislocations in the matrix. With the increase of the volume fraction and the size of the SiC particulates, the tensile strength, elastic modulus and Brinell-hardness of the composites increase, while elongation ratio decreases. Because of the small clusters of the micro-sized particles, the yield strength of the small diameter SiC particles reinforced composites is lower than that of the large diameter SiC partiles reinforced ones. The results show that the SiC/ZA27 composites with SiC particulates uniformly disperse in the matrix, and good cohesion between SiCp and ZA27 is believed to be the result of the cooperative effects of acoustic cavitation and high speed acoustic streaming in ZA27 alloy melt.
Key words: SiCp/ZA27； high-intensity ultrasonic； mechanical properties； strengthening mechanism