Tungsten carbide (WC) matrix composites toughened by commercial alumina (Al2O3) composed of boehmite (AlOOH), χ- Al2O3 and amorphous Al2O3 (WA1) and α-Al2O3 (WA2), respectively, were prepared by high energy ball milling and the following hot pressing, respectively. The microstructure and mechanical properties of WA1 and WA2 were characterized and compared. The results showed that the content of ditungsten carbide (W2C) in the sintered WA1 composites was much smaller than that of WA2 because the phase transformation of the commercial Al2O3 in WA1 suppressed the decarburization of WC; The Vickers hardness and fracture toughness of WA1 were higher than that of WA2 due to the smaller WC grain size and Al2O3 particulate size resulted from the phase transformation of the commercial Al2O3 in WA1. The lower density and worse particulate/matrix interfacial combining conditions of WA1 compared with that of WA2, resulting from the phase transformation of the commercial Al2O3, were responsible for its lowered flexural strength.

Keywords: WC matrix composites, Hot pressing sintering, Mechanical properties, Microstructure-final.