Lower volume fraction SiC_P/AL composites fabricated by squeeze infil tration casting

摘要

The volume fraction of particulate reinforcement in an aluminum composite fabricated by squeeze infiltration casting is alway about 50 vol percent or higher. To make lower volume fraction composites (0-25 vol percent), a mixed preform, composed of pure aluminum powder and SiC particles, was used and squeeze cast by a low melting-point alloy (AA383). Reinforcement macro-distribution uniformity and successful infiltration suggest that the suitable processing parameters are: melt temperature, 750 deg C; preform temperature, 515 deg C; infiltration pressure, 75 MPa; ram speed, 4 mm/s. Microstructure analysis shows that SiC_P distributed uniformly and no pore was observed for all the composites with various volume fraction or size of particulate reinforcement. The tensile properties of 85 #mu#m SiC_P/Al/A383 composites (0-25 vol percent) are better than that of A383 alloy though pure Al has a low strength. It is resulted from the refinement of silicon plates.