Microhardness and Microstructure of In-Situ Formed Fe-50%TiC Composites by Different Heating Methods

Abstract

The aim of this study is to fabricate in-situ TiC particle reinforced Fe matrix composites via volume combustion synthesis (VCS) through heating by two different sources. One group of reactant pellets was ignited by heating in an induction furnace (IF). The other group was ignited via heating by using a tungsten inert gas (TIG) torch. Thus, the differences in the microhardness and microstructure of the obtained composites could be compared. Fe, C and Ti elemental powders were used to obtain composites that contained 50 vol. % TiC in the Fe matrix. In the repeated experiments, the ignition temperatures of the IF pellets were found to be in 1164-1184 oC range. The formation of composites was verified by X-ray diffraction (XRD) analyses, where it was seen that the products were composed of TiC and Fe with trace impurity phase. Scanning electron microscope (SEM) examinations showed that the in-situ formed TiC particles were regularly distributed in matrix in both series. The TiC particles obtained by TIG heating were about 5 times larger than the particles obtained by induction heating. Microhardness values of the samples were higher in IF series as compared to TIG series. It was shown that 50 vol. % TiC particle reinforced Fe matrix composites could be obtained by both heating methods. TIG was found to be a much practical method, when compared to conducting VCS in a furnace.