Effects of Cr₃C₂ Addition on Microstructure and Mechanical Properties of TiC/Ti Composites

Taking Cr₃C₂ powders as the carbon source and titanium sponge as the matrix, in situ formed TiC/Ti composites were prepared by using a vacuum induction suspension melting furnace. The effect of Cr₃C₂ additions (3wt%, 6wt%, 9wt%) on the microstructure and mechanical properties of the composites was investigated. The physical phase composition and microstructure of the composites with different Cr₃C₂ additions were characterised by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Mechanical properties of composite materials were tested by using Rockwell hardness tester and room temperature tensile properties tester. The results show that with the increase of the addition of Cr₃C₂, the morphology of TiC changes from elongated strips to equiaxed and then to dendritic, the microstructure of the matrix changes from lamellar α' to acicular martensite α', and the grain size decreases dramatically. With the increase of Cr₃C₂ content, the Rockwell hardness of the composites increases from 12.2 HRC to 40.2 HRC, the tensile strength and elongation rises firstly and then falls. When the addition amount of Cr₃C₂ is 6.0 wt%, the tensile strength and the elongation are the maximum.