Abstract:The effects of compocasting process parameters on some structural and tensile characteristics of the A356-10% SiC_p (volume fraction) in;, 600 ognized by weak composites were studied. Semisolid stirring was carried out at temperatures of 590, 600 and 610 °C with stirring speeds of 200, 400 and 600 r/min for 10, 20 and 30 min. The distribution of the SiC particles within the matrix, porosity content and tensile properties of the obtained samples were examined. The structural evaluations show that by increasing the stirring time and decreasing the stirring temperature, the uniformity in the particle distribution is improved; however, by increasing the stirring speed the homogeneity firstly increases and then declines. It is also found that by increasing all of the processing parameters, the porosity content is enhanced. From the tensile characteristics viewpoint, the optimum values of the speed, temperature and time are found to be 400 r/min, 590 °C and 30 min, respectively. The contribution of the reinforcement distribution uniformity prevails over that of the porosity level to the tensile properties.

Key words: A356-SiC_p composite; semisolid stirring; compocasting; porosity; reinforcement distribution; tensile properties