Abstract
An in-situ composite consisting of titanium carbide and iron aluminide was synthesized by mechanical alloying of the powder mixture of titanium, carbon iron and aluminum followed by pulse discharge sintering. Nominal composition of milled powders was (Fe-28at%Al)-9.6at%Ti-9at%C. Milling up to 50 h causes the X-ray peak broadening of elemental powders due to the fragmentation of the crystallites. The variation of the lattice parameter during milling suggests that the formation of iron solid solution starts at 100h and is completed at 150h. Mechanical alloying also leads to the extension of solid solubility. After milling for 1h to 400h, pulse discharge sintering was carried out at 1273 K, 1373 K and 1473 K, respectively. Fe3Al and TiC precipitate from the supersaturated iron solid solution containing aluminum, titanium and carbon by sintering. The microstructures of the composites consist of large TiC particles of about 5μm in diameter, iron aluminide regions containing TiC particles with sub-micron sizes and the regions of particle-free iron aluminide at all sintering conditions.
