Effect of rare earth Y addition on the microstructure and mechanical properties of Ti(C,N)-304ss cermets

Abstract

Ti(C,N)-304ss cermets with various rare earth yttrium addition were fabricated via powder metallurgy. Fe and Cr atoms dissolved into Ti(C,N) grains and formed a core-rim structure. The first-principle method was employed to calculate the lattice parameters and elastic modulus of the solid solution. The formation of solid solution not only reduced the lattice misfit between the binder phase and hard phase but also improved the hardness of hard phase. The in-situ formed nano-Y2O3 particles existed at the center of Ti(C,N) grains acting as ‘mid effect’ heteromorphic nuclei. The microstructure of cermets was refined with Y addition and the abnormal growth of hard phase was suppressed. The mechanical properties were also improved with Y addition. When the Y content reached 0.3 wt%, the optimal mechanical properties were obtained with a TRS value of 1527 MPa and a hardness value of 91.7 HRA.