Effect of Cr3C2 on microstructure and mechanical properties of WC-Cu-10Ni-5Mn-3Sn cemented carbide

The effect of small contents of Cr3C2 (0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 wt.%) dopant on the microstructure and mechanical properties of WC-Cu-10Ni-5Mn-3Sn alloy is investigated via pressureless melt infiltration tests at the temperature of 1210 ℃ and the infiltration time of 1.5 h. The results show that with the addition of Cr3C2, the amounts of Cr, W and C in solid solution in the binder alloy changes, and Ni2W4C and Cr7C3 appear successively in the binder alloy, and Cr7C3 readily absorbs W produced by the decomposition of WC to form (W,Cr)Cx and (Cr,W)C. The appearance or disappearance of the new phases leads to the changes in the grain size of the WC, which affects the mechanical properties of the alloy. The hardness and transverse rupture strength showed a trend of first increase and then decrease with the increase of Cr3C2 addition, and the hardness and transverse rupture strength reached the maximum value when the Cr3C2 addition was 0.4 wt.% and 0.6 wt.%, which were 93.1 HRA and 1720 MPa, respectively. The impact toughness decreases with increasing Cr3C2 addition and the best impact toughness value of 4.65 J·cm-2 was obtained for the alloy without Cr3C2 addition.