Preparation, microstructure and mechanical properties of steel matrix composites reinforced by a 3D network TiC ceramics

Abstract

In this study, the porous TiC ceramics were fabricated using the foam replication-reaction sintering method, by adding 20 wt% metal Ti to TiC either through uniform mixing or cladded as a layer on TiC to modify the porous ceramics' strength. Subsequently, the porous TiC ceramics were used as a reinforcement to develop the interpenetrated three-dimensional (3D) network TiC/45 steel composites by employing the melt infiltration method. XRD and SEM analysis confirmed that the Ti-coated porous TiC ceramics possessed a TiC core, an intermediate TiCx zone and a dense outer mixed Ti and TiCx layer. As the composition changed from pure TiC to Ti-coated TiC, the porosity of the porous TiC ceramics decreased from 94.3% to 89.3%, along with an increase in compressive strength from 0.90 MPa to 2.33 MPa. No impurity was observed in any of the 45 steel matrix composites. The composites reinforced with the Ti-coated porous TiC ceramics displayed a continuous 3D network structure reinforcement, while the network structure of Ti mixed porous TiC ceramics reinforcement in the composites was weakly continuous. Both macro and micro double interlocking 3D structures in the composites with Ti-coated network ceramics resulted in excellent hardness, tensile strength and fracture toughness, with the values determined to be 4.11 GPa, 481 MPa and 28.9 MPa m1/2, respectively.