Processing of (W,Ti)C/Fe composites by pressureless Ti-activated reactive melt infiltration

As a new kind of method to prepare composites, pressureless Ti-activated reactive melt infiltration was investigated. The Ti-WC porous ceramics skeleton preform was prepared by gelcasting using sugar as pore former. Under vacuum condition, the Ti-WC porous ceramics skeleton preform was infiltrated by Fe-Cr-C alloy melt with in-situ reaction to prepare the (W,Ti)C/Fe composites. The microstructures, element composition and phase analysis were investigated by using SEM-EDS and XRD. And the wear resistance was studied using a rotating disc rig with SiC mortar as the abrasive material. The results show that the infiltration process is accelerated by the dissolution and precipitation of titanium and the in-situ reaction between titanium and carbon. At 1370℃ for 1 h, the porous ceramics skeleton is permeated by the melt, and the space structure has not been changed in the infiltration process. The reinforced phase (W,Ti)C which has a concentration gradient of Ti and W from core to the periphery is produced by in-situ reaction of Ti-C-WC. As the result of the wear testing shown, (W,Ti)C/Fe composites have excellent abrasive wear resisitance, which is better than that of the wear resistant cast iron commonly used in industry.