Consolidation of B4C-VB2 eutectic ceramics by spark plasma sintering

The in situ synthesis and consolidation of B4C-VB2 eutectic composites by spark plasma sintering (SPS) is reported. The microstructure properties were determined for composites with the B4C-VB2 eutectic composition as functions of the VB2 content and the VB2-VB2 interlamellar spacing. A change of VB2 concentration from 45 to 48 mol.% resulted in the formation of the rodlike eutectic microstructure. Indentation fracture toughness values higher than 4 MPa.m(1/2) were identified for eutectic composites with interlamellar spacings between 0.9 and 1.2 mu m. The composites obtained by SPS with a composition of 45 mol.% VB2 exhibited a lower Vickers hardness (23-24 GPa) and higher indentation fracture toughness (up to 4.5 MPa.m(1/2)) than the eutectic composites with 48 mol.% of VB2. (C) 2015 The Ceramic Society of Japan. All rights reserved.