《Casting of SiC Reinforced Metal》.pdfVIP

W. Zhou, Z.M. Xu / Journal of Materials Processing Technology 63 (1997) 358-363 Casting of SiC Reinforced Metal Matrix Composites W. Zhou*, Z. M. Xu** * School of Mechanical and Production Engineering Nanyang Technological University, Nanyang Avenue, Singapore 639798 ** Singapore Aerospace Manufacturing Pte. Ltd. 503 Airport Road, Paya Lebar, Singapore 539932 Contact Prof. Wei Zhou for further information through e-mail WZhou@Cantab.Net Abstract Composites based on two aluminium alloys (A536 and 6061) reinforced with 10% or 20% volume fraction of SiC particles were produced by gravity casting and a novel two-step mixing method was applied successfully to improve the wettability and distribution of the particles. The SiC particles were observed to be located predominantly in the interdendrit ic regions, and a thermal lag model is proposed to explain the concentration of particles. It was found that the SiC particles acted as substrates for heterogeneous nucleation of Si crystals in one of the cast composites. This observation can also be explained by the thermal lag model proposed. Keywords: casting, metal matrix composites, wettability, particle distribution, and thermal lag. 1. Introduction cost efficiency. In the present work, a two-step mixing method was tried in hope of producing cast composites with better Composite materials are continuously displ