Microstructural evolution and mechanical properties of hot pressed WC–α-Al₂O₃ with Y₂O₃ and CeO₂

Abstract

WC–α-Al₂O₃ composites, with the rare earth oxides (Y₂O₃ or CeO₂) as sintering additives, were fabricated by mechanical alloying and hot pressing sintering. The microstructure and mechanical properties of WC–Al₂O₃ with and without oxides were investigated. The appearance of rare oxides increased the density of sintered bulk materials and suppressed the decarburisation due to the decrease of surface activation energy in sintering process. The hardness and fracture toughness of the samples first increased and then decreased, indicating that an appropriate addition of Y₂O₃ or CeO₂ could strengthen the properties of samples. Microstructure observation results revealed that the grain growth of WC was significantly retarded, and the homogeneity of Al₂O₃ particulate dispersion was improved with the addition of Y₂O₃ and CeO₂.

Keywords:

• Hot pressing
• Mechanical property
• WC–Al2O3 composites

Acknowledgement

We would like to acknowledge the support of Chinese Universities Scientific Fund (grant no. 14D310303).