In situ fabrication of TiC particulates locally reinforced aluminum matrix composites by self-propagating reaction during casting

摘要

TiC ceramic particulates locally reinforced aluminum matrix composites were successfully fabricated via self-propagating high-temperature synthesis (SHS) reaction of Al-Ti-C system during aluminum melt casting. The SHS reaction could be initiated when Al contents in the green compacts ranged from 20wt.% to 40wt.%. With increasing Al contents, the ignition delay time was prolonged and the adiabatic combustion temperature was lowered. Using XRD and DSC analysis, the SHS reaction characteristic was discussed. The result showed that Al serves not only as a diluent but also as an intermediate reactant participating in the SHS reaction, determining the reaction process and its final producsts. The SEM images revealed a relatively uniform distribution and nearly spherical morphology of TiC particulates in the locally reinforced region, and excellent adhesion and gradient distribution between the TiC particulates reinforced region and Al-matrix. The size of the TiC particulates decreased obviously with increasing Al contents in the blends.