Hardness and fracture-toughness of hot-pressed LaB6-TiB2 ceramics

Abstract

Abstract Microstructural analysis and investigations of mechanical properties via indentation-techniques have been performed on a LaB6 - 15 vol. % TiB2 ceramics, obtained by the hot-pressing at T = 1900 °C and P = 30 MPa in argon gas. The relative density of hot-pressed material was up to 97% of theoretical. XRD, SEM and EDX analysis of ceramics were performed. The Vickers hardness (18.5 GPa) and fracture-toughness (3.9 MPa-m1/2) were compared with the values, measured on a single-crystalline LaB6 (Hv = 21 GPa, KIc = 2.4 MPa-m1/2) and arc-melted eutectic composite LaB6-TiB2 (Hv = 23 GPa, KIc = 6.7 MPa-m1/2).