Effect of V Addition Amount on Microstructure and Mechanical Properties of Mo₂FeB₂-Based Cermets

Mo₂FeB₂-based cermets were prepared by vacuum liquid phase sintering technique. The effect of V addition amount (0-7.5wt%) on the microstructure and mechanical properties of cermets was investigated. The results show that the porosity of cermets had little change when V addition amount was not more than 2.5wt%. When V addition amount was more than 2.5wt%, pores in cermets increased obviously and the relative density of cermets decreased. V addition had no effect on the phase composition of cermets, and Mo₂FeB₂ hard phase was uniformly distributed in the iron-base bonding phases. When the V addition amount was 2.5wt%, hard phase was long ribbon shape and was obviously refined. When V addition amount exceeded 2.5wt%, hard phase agglomerated and its morphology changed from long ribbon shape to equiaxial shape. With the increase of V addition amount, the hardness, rupture strength and fracture toughness all first increased and then decreased, and reached their maximum values with V addition amount of 2.5wt%, which were 90.6 HRA, 2 350 MPa and 15.1 MPa·m^1/2, respectively.