Microstructure and tribological properties of Cr3C2/Ni3Al composite materials prepared by hot isostatic pressing (HIP)

Abstract

Ni3Al-based composites with different Cr3C2 contents were fabricated by the hot isostatic pressing (HIP) technique. The microstructure, phase constitution, and tribological properties of the composites were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and pin-on-disk wear tests. The results revealed that the strengthening phase is distributed homogeneously in the Ni3Al matrix. During the HIP process, M7C3 (M=Cr, Fe) is formed by diffusion of Fe, C, and Cr to the interface between the Cr3C2 particles and Ni3Al matrix. The diffusion process binds the phases and is important for improving the wear resistance of Cr3C2/Ni3Al composites. The wear measurements demonstrated that micro-cutting and fatigue wear are the dominant mechanisms for this tribological pair. The wear resistance of Cr3C2/Ni3Al composites is significantly improved by the addition of Cr3C2 particles. When the content of Cr3C2 is within a certain range, the wear resistance of Cr3C2/Ni3Al composites increases as the Cr3C2 content increases. However, the addition of excess Cr3C2 (for example, 24vol% in this work) could lead to a decrease in the wear resistance of the composites. In addition, the average friction coefficients and wear of the counterpart decrease with increasing Cr3C2 addition.