Sintering and mechanical properties of TiB2-TiC-Ni using submicron borides and carbides

Abstract

A series of TiB2-TiC-Ni composites were prepared to develop materials with enhanced mechanical properties for structural application. Submicron TiB2-TiC powders were synthesized using a patented carbon coated precursor method. The composites had about 99% relative density after sintering at a temperature of 1550°C in flowing argon. TiB2-TiC-Ni composites showed superior sintering and mechanical properties comparing with monolithic TiB2 and TiC counterparts because of the enhanced microstructures. Phases, grain morphologies, pores sizes, sintering behaviors, and mechanical properties were correlated with the ratio of TiB2/TiC and Ni content. The plate like TiB2 grains were observed in the composites. Toughening mechanism was determined as metallic binder plastics deformation, bridging, and debonding of the TiB2/TiC interface. TiB2-TiC-Ni composites have good combinations of hardness and fracture toughness as 24.23GPa, 7.41MPam1/2, and 21.85GPa, 8.44MPam1/2, with Ni content of 5 and 10wt%, respectively.