High wear resistance WC-Co reinforced GCr15 bearing steel composite prepared via selective laser melting (SLM)

Abstract

Among numerous reinforced particulates, WC-Co particles are regarded as a promising reinforcement for Fe matrix composites to enhance the tribological properties. Because of the particles’ high chemical stability, and high hardness. In this study, WC-Co particles were chosen as reinforcements to produce GCr15 bearing steel matrix composites by SLM. The microstructures and friction performance of the composites were observed and analyzed. The effect of the laser line energy density (LED) on phases, microstructure and friction performance features is investigated systematically. The phase of samples added with WC-Co particles changed obviously, from mainly α-Fe to γ-Fe. At the same time, Fe7C3, WC, CrSi2, M3W3C phases were found in the composites. The composite prepared by SLM has a good inter-reaction interface between the GCr15 bearing steel matrix and WC-Co particles. Two special microstructures, nail-shaped and cellular microstructure were found in the composites, and with the increase of LED, the size of the cellular microstructure increased, maximum average size is 1.45 μm. After adding WC-Co particles, the properties of GCr15 bearing steel were significantly enhanced, and the microhardness increased from 651 ± 61 HV0.2 to 1093 ± 139 HV0.2, and the COF and wear rate decreased from 0.5091 and 1.82 ± 0.17 × 10−6 mm3N−1 m−1 to 0.4116 and 0.58 ± 0.11 × 10−6 mm3N−1 m−1, respectively