Microstructure and mechanical properties of B4C–HfB2–SiC ternary eutectic composites prepared by arc melting

In order to improve the hardness and toughness simultaneously, B 4 C–HfB 2 –SiC ternary composites were synthesized by arc-melting using B 4 C, HfB 2 and β-SiC powders as raw materials. The ternary eutectic composition of 45B 4 C–15HfB 2 –40SiC (mol%) was first identified with a lamellar eutectic texture. HfB 2 about 500   nm in thickness and SiC about 700   nm in thickness were uniformly dispersed in B 4 C matrix of the eutectic composite, much smaller than raw powders. The Vickers hardness and fracture toughness of B 4 C–HfB 2 –SiC ternary eutectic were 35.7   GPa and 6.5   MPa m 1/2 at the eutectic composition, respectively.