PROCESSING AND PROPERTIES OF BORON CARBIDE WITH HAFNIUM DIBORIDE ADDITION
This article presents the results of investigations on densification, mechanical and electrical properties of boron carbide (B4C) with the addition of HfB2. High dense B4C HfB2 (2.5 30 wt composites were prepared by hot pressing at a temperature of 2173 K with 40 MPa mechanical pressure. The B4C HfB2 composite mixture exhibited a better sintering aptitude compared with monolithic B4C. Hardness and elastic modulus of B4C HfB2 composites were measured to be in the range 36 28 GPa and 465 525 GPa respectively. Indentation fracture toughness of B4C increased with HfB2 content and obtained a maximum of 7 MPa m at 30 wt. HfB2, which is ~3 times higher than the monolithic B4C. Crack deflection was identified to be the major toughening mechanism in the developed composite. B4C 10 wt. HfB2 composite exhibited a maximum electrical conductivity of 7144 O m which is 26 higher than the conductivity of monolithic B4C (5639 O m) at 1373 K.