Influence of molybdenum content and load on the tribological behaviors of in-situ Cr3C2-20 wt % Ni composites

Abstract In this study, Mo elements (0.5 wt %, 1.0 wt %, and 1.5 wt %) were doped by the powder metallurgic method to improve the abrasion resistance of in-situ Cr3C2-20 wt % Ni composites. The dry sliding friction experiments against Al2O3 ceramic were systematically investigated under different loads (25 N, 50 N, 75 N, and 100 N) at room temperature. Experimental results indicated that the hardness, bending strength, and fracture toughness of Cr3C2-20 wt % Ni composites increased with an increase in the Mo content due to the grain refinement and solution strengthening. The coefficient of friction and wear rate of theses composites risen with an increase in the load, thus changing the wear mechanism from abrasive wear and partial oxidation wear to serious fatigue wear. The tribological behaviors of in-situ Cr3C2-20 wt % Ni composites were obviously improved by doping Mo, which accomplished by the superior mechanical properties of Cr7C3 phases and the formation of lubricated MoO3.