Production of Hypo-eutectic Al-Si Alloy Based Metal Matrix Composite with Thixomoulding Processing

In this study, hypo-eutectic A356/SiC(p) metal matrix composite production was made with thixomoulding. For this purpose, A356 (Al-Si) alloy was put in the form of powder in <= 50 mu m level produced using gas atomization method. 5%, 10%, 15% and 20% SiC(p) reinforcement was added and they were mixed in a mixer for 30 minutes. Then, the mixed powders were pressed for 1 min under 20 kN force at 823 K mould and 863 and 873 K process temperatures. Optical and scanning electron microscopy (SEM) investigation and sphericity, grain size and micro hardness measurements were carried out on the produced composites. It was observed that thixomoulding resulted in spherical grain structure rather than dendritic structure. The most ideal sphericity was obtained for the specimens produced at 823 mould and 863 K process temperatures. Increasing SiC(p) reinforcement decreased % sphericity rate and increased grain size and hardness.