The effect of TiC on structure and hardness of WC-Co composites prepared using various consolidation methods
Jan Dutkiewicz, Magdalena Szutkowska, Wojciech Leśniewski, Piotr Wieliczko, Andrzej Pieczara, Łukasz Rogal
Quarterly No. 2, 2014 pages 91-95
DOI:
keywords: cemented WC-TiC-Co carbides, HIP and SPS consolidation, hardness and fracture toughness measurements
abstract The additions of 5÷10 wt.% TiC to WC-Co industrial composites substituting WC were consolidated using either the Hot Isostatic Pressing (HIP) method at the temperature of 1320°C and pressure of 250 MPa, or using the Spark Plasma Sintering (SPS) method. The latter samples show a hardness increase from 1050 HV (without TiC) up to 1330 HV at 5% TiC. A larger addition of 10% TiC allows one to obtain a similar hardness increase as in the case of the 5% addition. A higher hardness of 1570 HV was observed for samples consolidated using HIP, which can be explained by the higher consolidation pressure of 1500 bars and temperature of 1350°C leading to a lower porosity. The crack formation behavior allowed the authors to determine the fracture toughness, KIC, in the range of 10.9÷11.2 MPam1/2 for the samples containing 0÷10% TiC. Three phases were identified using the X-ray diffraction method, as well as scanning and transmission electron microscopy. The major identified phase is WC particles separated by a narrow layer of Co and are accompanied by single particles of TiC. It indicates that TiC do not form a common solid solution with WC as also confirmed by EDS chemical analysis, which was suggested in literature.