In-situ fabrication of TiC-Fe3Al cermet

Abstract

Titanium carbide has high hardness, resistance to oxidation and abrasion while iron aluminide has proper ductility as well as good strength and excellent oxidation resistance up to high temperatures. Therefore, it can be expected TiC-iron aluminide cermet to have excellent mechanical properties as a cutting tool and a wear-resistance material. In this study, mechanical milling and hot press sintering processes were used to manufacture in-situ TiC-Fe3Al cermet, whose microstructure and mechanical properties were examined according to the changes in volume fraction of TiC and milling time. After 48h of milling each mechanically alloyed powder crystallized in a TiC and Fe3Al biphasic material. The milled powder was hot-pressed at 1250℃ and 50MPa for 30min to obtain sintered bodies also consisting of only TiC and Fe3Al phases. The hard phase, TiC, had a size of 100–300nm with overall uniform distribution decreasing as the volume fraction of TiC increased. The hardness of each sintered body showed a linearly increasing tendency according to the increase in TiC content, the hardness for 90vol% TiC cermet being as high as 1813Hv. On the other hand, the bending strength was 1800MPa and 1780MPa when TiC volume fraction was 50% and 70%, respectively, while it showed an abrupt decrease up to 580MPa at 90% TiC volume fraction. Fe3Al phase is effective to toughening of TiC-Fe3Al cermet and the volume fraction of Fe3Al phase significantly influences the bending strength of the cermet.