Thermal explosion synthesis of aluminum matrix composites reinforced with TiC-TiB{sub}2 ceramic particulates

摘要

In situ TiC-TiB{sub}2 diphase ceramic reinforced aluminum metal matrix composites were successfully fabricated via thermal explosion (TE) reaction in the Al-Ti-B{sub}4C system. Using DTA and XRD analyses, the combustion reaction characteristic was examined. The results show that Al serves not only as a diluent but also as a reaction participant, affecting the reaction process and its final products. Combining with the DTA and the TE temperature-time curves, the ignition temperature is estimated to be about 970K. With increasing Al content, the adiabatic combustion temperature is lowered and the sizes of the TiC and TiB{sub}2 particulates decrease. When the Al content in the reactants is more than 50%, Al{sub}3Ti intermediate phase is detected in the synthesized products. SEM observations reveal that the nearly spherical TiC particles and hexagonal or rectangular TiB{sub}2 particles distribute relatively uniformly in the Al matrix.