Discontinuous Reinforced MMC (Metal Matrix Composites) by Improved Sonic Distribution of SiC into Molten Aluminum

摘要

A 20-month program investigated the use of sonic energy to form a discontinuous SiC/Al metal matrix composite system. Predicated on the previous Phase I SBIR effort, this Phase II program involved the use of a sonic transducer to distribute SiC particulate into melts of molten aluminum. Although the program was plagued with the major problem of finding equipment which would operate under the necessary conditions, such a unit was identified and procured. Additions of 10 wt% were attempted with 520, 356, and pure aluminum. Greatest success was achieved with the 520 alloy, followed by the 356 alloy with successful additions of 10 and 7 wt%, respectively. Further, distribution of the particulate was fairly uniform. Other alternative methods of producing discontinuous SiC/Al were also investigated including mixing with an impeller and use of a proprietary coating on the SiC particulate. Keywords: Metal matrix composites; Discontinuous reinforcement; Silicon carbide; Sonic energy.