The influence of (Ti,W)C and NbC on the mechanical behavior of alumina

Recent studies published in the literature have focused on reinforcing alumina with different refractory carbides and nitrides in order to improve hardness, fracture toughness and wear resistance. The incorporation of hard particles as WC, (Ti,W)C and NbC on alumina matrix has shown to be a good alternative in improving the mechanical properties of the composite material. The present work reports some preliminary results obtained reinforcing alumina with 20 wt. (%) (Ti,W)C and 10 wt. (%) NbC. Alumina, (Ti,W)C and NbC powders were homogenized and mixed in a planetary ball mill and subsequently hot-pressed at 1650 °C under 20 MPa in flowing argon. Specimens were characterized by Vicker's microhardness (H V), fracture toughness (K IC), X ray diffraction and scanning microscopy. The composite material showed hardness values of 19.5 GPa and fracture toughness values <FONT FACE=Symbol>»</FONT> 5.2 MPa.m½. The high fracture toughness encountered in this work is related to the crack deflection mechanism