In Situ NbC Particulate-Reinforced Iron Matrix Composite: Microstructure and Abrasive Wear Characteristics

Abstract

An niobium carbide (NbC) particle-reinforced iron matrix composite was fabricated by compounding gray cast iron with niobium wires through an in situ technique comprised of an infiltration casting process and a subsequent heat treatment. The NbC particles in the reinforcement phase were synthesized in situ through the reaction between niobium from niobium wires and carbon from the graphite phases produced by the heat treatment in gray cast iron. The microstructure and wear-resistance of the bulk niobium particle-reinforced iron matrix composite was studied at different NbC particle volume fractions (8, 15, 22, and 28 vol%), by scanning electron microscope, X-ray diffraction, and a wear tester. The NbC particles were observed to form tiny cuboids and nearly spherical particles which were evenly distributed in the matrix. The particle size of the NbC reinforcement was about 0.3–3.5 μm. The relative wear resistance of the bulk composite increased with increasing NbC volume fraction, and the wear resistance of the composite was 5.9-fold higher than that of the gray cast iron under a 20N load and at a 28 vol% volume fraction. Wear performance of the composite at different NbC particle volume fraction values was also analyzed.