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

The WC‒Cu‒10Ni‒5Mn‒3Sn cemented carbide doped with Cr₃C₂ was prepared by pressureless melt infiltration at 1210 ℃ for 1.5 h, the effect of Cr₃C₂ dopant (0.0, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%, mass fraction) on the microstructure and mechanical properties of the WC‒Cu‒10Ni‒5Mn‒3Sn alloys was investigated. The results show that during the infiltration process, the WC particles partially decompose with the addition of Cr₃C₂, the Ni₂W₄C and Cr₇C₃ appear in the alloys, and the (W,Cr)C_x and (Cr,W)C are formed from Cr₇C₃ and W produced by the decomposition of WC. The emergence of new phases causes the change in WC grain size, thereby altering the mechanical properties of the alloys. With the mass fraction increase of Cr₃C₂, the hardness and flexural strength show the trend of first increasing and then decreasing. When the mass fraction of Cr₃C₂ is 0.4% and 0.6%, respectively, the hardness and flexural strength reach the maximum, which is HRA 93.1 and 1720 MPa, respectively. The addition of Cr₃C₂ is not conducive to the impact toughness, the alloys without Cr₃C₂ have the highest impact toughness as 4.65 J·cm^‒2.