Tribological behaviors and microstructure evolution of Inconel 718 superalloy at mid-high temperature

Abstract

Revealing the microstructure evolution of materials during the sliding process is crucial to their long-term application. In this study, the friction and wear behaviors of Inconel 718 under different conditions were systematically investigated. The wear surface and detailed microstructure evolution of Inconel 718 after sliding were also characterized by three-dimensional (3D) profilometry, scanning electron microscopy (SEM-EDS) and electron backscattered diffraction (EBSD). The results indicated that the applied load and test duration significantly influenced the tribological performance and microstructure evolution of Inconel 718. Under an applied load of 3 N, the main wear mechanisms of Inconel 718 gradually changed from single adhesive wear to mixed adhesive and abrasive wear as the test duration increased. However, the wear mechanisms of Inconel 718 were continuously dominated by adhesive wear and oxidative wear under a load of 5 N. Furthermore, clear lattice distortion occurred on the rubbing area, as observed by the EBSD characterization, resulting in the nucleation and propagation of microcracks during the rubbing process. In this case, the material was peeled off from Inconel 718 under the action of friction when the microcracks expanded and interconnected. These results have significance in guiding the application of Ni-based superalloys in aeroengines.