Preparation of B4C–ZrB2–SiC ternary eutectic composites by arc melting and their properties

Abstract

B4C–ZrB2–SiC composites were synthesised by arc melting in Ar atmosphere using B4C, ZrB2 and β-SiC powders as starting materials. The ternary eutectic composition of 40B4C–20ZrB2–40SiC (mol-%) was first identified and a lamellar eutectic texture was observed. SiC and ZrB2 grains about 1 μm in thickness were uniformly dispersed in B4C matrix of B4C–ZrB2–SiC eutectic composite. B4C (003) and ZrB2 (100) planes were perpendicular to the growth direction. The Vickers hardness of B4C–ZrB2–SiC ternary eutectic composite was 30–34 GPa. The fracture toughness of B4C–ZrB2–SiC composite increased with the decrease of B4C content and the rise of ZrB2 content.