Consolidation and characterization of highly dense single‐phase Ta–Hf–C solid solution ceramics

Abstract

AbstractHerein, Ta–Hf–C solid solution ceramics were consolidated from nano‐scale Ta–Hf–C solid solution powders for the first time. Four different compositions (4TaC–1HfC, 1TaC–1HfC, 1TaC–3HfC, and 1TaC–4HfC) were prepared by hot‐pressed sintering at 2100°C, 70 MPa pressure and a holding time of 30 minutes. The densification, formation of single‐phase solid solution and mechanical properties of the samples were systemically investigated. Relative density >95% was achieved for all four compositions with some improvement when TaC content was increased. And the formation of single‐phase Ta–Hf–C solid solution was strongly demonstrated by phase analysis and crystal measurement using XRD and TEM. A significant improvement of hardness up to ~30 GPa was achieved, which was much higher than that of pure TaC (18.9 GPa) and HfC (22.1 GPa), due to the high densification and solid solution strengthening mechanism.