Effect of Mo addition on microstructure and mechanical properties of (Ti,W)C solid solution based cermets

Abstract

(Ti,W)C solid solution was synthesized by milling a mixture of C and oxides and then reducing it at 1350°C for 2h. The microstructure and mechanical properties of (Ti,W)C solid solution based cermets with various Mo additions were systemically studied. The dark core–gray rim carbide grains and/or gray carbide grains embedded in black Ni based binder phase were observed. The grain size of the cermets decreased with increasing Mo addition, while excessive Mo addition would result in agglomeration and inhomogeneity of the grains. The dark core was transformed from (Ti,W)C into (Ti,W,Mo)C and Mo concentration in the dark core increased with increasing Mo content. The fracture toughness of the cermets decreased with the increase of Mo content, while the hardness and TRS reached a peak value at 10wt.% and 15wt.% Mo additions respectively, and declined with the further increase of Mo content.