Influence of ZrC addition on the microstructure, mechanical properties and oxidation resistance of Ti(C,N)-based cermets

摘要

In this study, Ti(C,N)-WC-NbC-ZrC-Co-Ni cermets were prepared by sintenng-hip at 1450 degrees C. The effect of ZrC addition on the microstructure, mechanical properties, oxidation resistance and wear resistance of Ti(C,N)-WC-NbC-Co- Ni cermets were explored in detail. The results show that ZrC addition plays the role of inhibitor in the dissolution-reprecipitation process, which can increase the wear resistant carbide phases and inhibit the pre cipitation of brittle (Ti,W,Nb)(C,N) rim phase. Therefore, the core-rim structures are refined and the Nb content in binder increases, which enhance mechanical properties and oxidation resistance of cermets. With the increasing ZrC content, the oxidation resistance of cermets can be improved constantly, while the transverse rupture strength, fracture toughness and wear resistance of these cermets increase first and then decrease. The cermet with 1 wt% ZrC exhibits the transverse rupture strength of 2549 MPa and highest fracture toughness of 13.0 MPa m(1/2). The oxidation weight gain of cermets containing 5 wt% ZrC after holding 100 h at 750 degrees C in air is 2.8 x 10(-6) g mm(-2), which is only 22% of that in the cermets without ZrC addition.