Effect of WC/TiC grain size ratio on microstructure and mechanical properties of WC–TiC–Co cemented carbides

Abstract: Microstructure and mechanical properties of WC–TiC–10wt%Co cemented carbides fabricated by sintering with hot isostatic pressing (Sinter-HIP) process were investigated. The WC/TiC grain size ratio of WC–TiC–10wt%Co cemented carbides was controlled by changing the average size of WC powders ranged from 0.5 to 4μm, with keeping the average size of TiC powder as 1μm. The microstructures of sintered WC–TiC–10wt%Co cemented carbides were sensitively dependent on the WC/TiC grain size ratio. In WC–TiC–10wt%Co cemented carbides with WC/TiC grain size ratio of 0.5, the TiC/(Ti,W)C core-rim phases were distributed in WC/Co matrix. While, in WC–TiC–10wt%Co cemented carbides with WC/TiC grain size ratio above 0.8, the WC and TiC/(Ti,W)C core-rim phases were surrounded by Co binder phase. Hardness of WC–TiC–10wt%Co cemented carbide increased with decreasing the WC/TiC grain size ratio from 4 to 0.8 following the modified Hall–Petch type equation. However, the hardness of WC–TiC–10wt%Co cemented carbides with WC/TiC grain size ratio of 0.5 shows much higher values than that expected by modified Hall–Petch type equation. Transverse rupture strength of WC–20TiC–10wt%Co cemented carbides increases with decreasing the WC/TiC grain size ratio. [Copyright &y& Elsevier]