Densification, microstructure and mechanical performance of TiC/Fe composites by spark plasma sintering

Abstract

In this study, the effects of the TiC content (10, 20, 30 and 40 vol. %) on the densification, microstructure, mechanical performance and friction properties of TiC/Fe composites were investigated. The combination of powder metallurgy (PM) method and spark plasma sintering (SPS) was used to prepare high-density TiC/Fe composites. The results show that the TiC/Fe composites experienced the dominating densification below 600 °C. The subsequent densification was restricted by the limited diffusion and dissolution between the TiC particles and Fe matrix, which has been verified by thermodynamic calculations in the present work. The hardness and bending strength of TiC/Fe composites improved until the maximum value, and then followed a decreasing trend with TiC content further increasing. The 20 vol. % TiC/Fe composite reached the highest bending strength of 1318 MPa, while the maximum hardness of 36.0 HRC was attained for the composite with 30 vol. % TiC. Fe binder plastic tearing, transgranular failure and intergranular failure were the main fracture mechanisms of TiC/Fe composites. In addition, the specific wear rate of the TiC/Fe samples increased with increasing TiC content, which should be ascribed to the severe oxidation of worn surfaces under load of 10 N and slide distance of 800 m.

Keywords

• TiC/Fe composites
• Spark plasma sintering
• Thermodynamic calculations
• Densification
• Mechanical performance