Abstract:TiC/Fe₃Al composites were fabricated rapidly by the combination of thermal explosion synthesis and spontaneous melt infiltration. The formation mechanism based on the phase composition and microstructure evolution process, TiC growth mechanism, sliding friction and wear properties of the resultant materials were investigated systematically. The molten Fe₃Al spontaneously infiltrates the pores of porous TiC compacts prepared by thermal explosion synthesis using Ti and C powders, resulting in the creation of TiC/Fe₃Al composites. The formation of TiC in final products can be attributed to dissolution-precipitation mechanism, i.e., TiC dissolves in Fe₃Al melt and decomposes into Ti and C, the latter reacts in the molten pool and precipitates the primary TiC and eutectic TiC during the cooling process. Fe atoms can enter the TiC lattice and be adsorbed preferentially at the {100} crystal plane, giving rise to reduce the surface energy of the {100} plane, so, the morphology of primary TiC changes from {111} octahedron to {100} cube. The TiC growth pattern is lateral growth of facet crystals, tending to grow layer by layer depend on more growth steps provided by the high cooling rate during the fabricate process. The sliding wear rate of TiC/Fe₃Al composites is 2.7×10^{-7 g/s, decreased by 31.7% compared with that of Fe}₃Al. The wear mechanism indicates that the wear resistance of the composites can be improved noticeably because the addition of TiC may effectively inhibit the delamination wear.

Key words: TiC/Fe₃Al; thermal explosion synthesis; pressureless melt infiltration; growth mechanism; wear