ساخت كامپوزيت نيمه جامد A1356/SiCp با تزريق پودر كامپوزيتي (A1-SiCp) cp به مذاب

Fabrication of A1356/SiCp semisolid composite by injection of Al-SiCp composite powder into the melt

In this study the effects of the casting temperature and the injected reinforcement form on properties of A1356-5vol.%SiCp composites were investigated. For this purpose, SiC particles were injected into the melt in two different forms, i.e., untreated SiCp and milled particulate AI-SiCp composite powder. AI-SiCp composite powder was prepared by low energy ball milling of equal volumes of pure aluminum powder with average diameter of about 80mm and SiCp powder with average size of about 8mm for 52 hours. The resultant composite slurries were then cast in either a fully liquid state (stir casting) or semisolid state (compocasting). Microstructure of the castings were then investigated in terms of the entrapmant and distrubution of the reinforcment particles in the matrix a well as the structure of the primary and secondary grains. The results showed that the incorporation and distribution of SiCp in the A1356 matrix alloy as well as the wetting of SiC particles with the matrix were greatly improved by injection of milled composite powder instead of untreated SiC particles into the melt and by casting in semisolid state instead of fully liquid state. Keywords: Metal matrix composites; A1356/SiC ; Compocasting; Composite powder