Sintering behavior of mechanically coated WC–Co/TiC–Al2O3 particles by high-speed rotational impact blending

The sintering behavior of WC–Co/TiC–Al2O3 composite has been investigated from its microstructure. The coated particles were prepared by high-speed rotational impact blending and sintered by spark plasma method (SPS) and hot press. The powder of the same composition was also mixed by means of an ordinary ball mill (BM) for comparison of their microstructural uniformities and mechanical properties. The microstructure was quantitatively measured on scanning electron microscopy photos by image analysis technique, and characterized by void size distribution curves. The results revealed that the sintered sample prepared with coated particles and with SPS possesses excellent morphological characteristics, such as smaller WC and Al2O3 mean grain sizes and uniform spatial distributions of hardest β-phase to yield higher mechanical properties such as hardness and transverse rupture strength than the cases of the BM and the hot press. The superior mechanical properties were obtained at higher sintering temperature with moderate sintering time of SPS.