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

Abstract

In order to improve the hardness and toughness simultaneously, B4C–HfB2–SiC ternary composites were synthesized by arc-melting using B4C, HfB2 and β-SiC powders as raw materials. The ternary eutectic composition of 45B4C–15HfB2–40SiC (mol%) was first identified with a lamellar eutectic texture. HfB2 about 500nm in thickness and SiC about 700nm in thickness were uniformly dispersed in B4C matrix of the eutectic composite, much smaller than raw powders. The Vickers hardness and fracture toughness of B4C–HfB2–SiC ternary eutectic were 35.7GPa and 6.5MPa m1/2 at the eutectic composition, respectively.