Characterization of Iron-Matrix Composites Reinforced by In Situ TiC and Ex Situ WC Fabricated by Casting

Abstract

In this study, the effect of microstructural characteristics on the mechanical properties of high-chromium white cast iron-matrix composites reinforced by in situ TiC and ex situ WC was investigated. To this end, two different powder mixtures (Ti + Al + graphite and WC + Fe) were compressed to produce green compacts that were inserted into the mold, before casting. The microstructure of the resulting composites and the base metal was characterized using optical microscopy (OM) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). The microstructural analysis revealed a sound bonding between the composite zone and the base metal. The reinforcement with WC particles showed a homogeneous distribution of the carbide particles, unlike the reinforcement with TiC particles. The mechanical properties of the reinforcements were evaluated using hardness and ball-cratering micro-abrasion tests. The results showed that both reinforcements increase the hardness and wear performance of the base material, which was the best performance achieved by the reinforcement with WC particles.

Keywords

• ex situ technique
• high-chromium white cast iron
• in situ synthesis
• local reinforcement
• microstructural characterization
• titanium carbide