Microstructure evolution of additively manufactured TiC reinforced graded metal matrix composite

Abstract

Ceramic reinforced metal matrix composites (MMCs) have advantages over traditional metallic materials, such as higher hardness, strength, and fracture toughness, which make them suitable for ballistic and defence applications. In this research, an in situ synthetized TiC reinforced Ti–Ni matrix sample was additively manufactured with Ti64 powders and Ni coated graphite powders. Input of Ni coated graphite powders increases from bottom to top of the sample to create a chemical gradient. Microstructure of the graded sample was examined using optical and scanning electron microscopy. The characterization results show that TiC dendrites are in situ synthesized within the metal matrix that contains α-Ti and Ti2 Ni. Morphologies and proportions of these phases change with the variation of chemical composition. Mechanisms of the evolution of microstructure are further analysed. The gradual variation of microstructures indicates that 3D printed graded MMC can provide gradient properties that are preferable for ballistic applications.