Development and Characterization of In-situ Aluminum-Titanium Carbide Composites Prepared by Pneumatic Powder Injection Route

摘要

High costs, consistency and scalability are the major challenges in development of metal matrix composites. To overcome these challenges, a novel process has been demonstrated in which pneumatic powder injection was used instead of the conventional mechanical stirring process. In this study, aluminum-titanium carbide particulate composites were prepared in situ by injection of mixed salt of titanium (K_2TiF_6-potasium titanium fluoride salt) and graphite powder through submerged lance into molten aluminum. Uniform distribution of equiaxed Al_3Ti (aluminum-titanium intermetallic) particles and TiC (titanium carbide) particles were achieved depending on the reaction temperature and holding time. SEM-EDS confirmed the presence of submicron TiC particles distributed throughout the matrix. TiC particles generated in situ are thermodynamically more stable and tend to have cleaner matrix particle interfaces. More than 15% improvement in elastic modulus along with significant improvement in other mechanical properties was achieved by up to 10 wt% TiC reinforcement.