In situ reaction and solid solution induced hardening in (Ti,Zr)B2‐(Zr,Ti)C composites

Abstract (Ti,Zr)B 2 ‐ (Zr,Ti)C ceramics were synthesized by reactive hot‐pressing and solid solution coupling effect using ZrB 2 and TiC powders as starting materials. Effects of sintering temperature on phase relations, microstructure and mechanical properties were reported. The equimolar ZrB 2 and TiC reactants ensured a complete in situ reaction to form (Ti,Zr)B 2 and (Zr,Ti)C solid solutions. The (Ti,Zr)B 2 ‐ (Zr,Ti)C composite sintered at 1750°C was fully densified, and exhibited a high hardness of 29.1 GPa due to fine‐grain hardening and solid solution hardening. The optimized comprehensive mechanical properties such as a hardness of 27.9 GPa, a strength of 705 MPa and an indentation fracture toughness of 5.3 MPa m 1/2 were achieved in (Ti,Zr)B 2 ‐ (Zr,Ti)C composites sintered at 1800°C for 1 hour.