Meanwhile, the amount of γ′ phase decreases, and δ phase is crushed and refined within the white layer. The results indicate that the thickness of the white layer is uneven and varies within three microns. After that, the morphology and microstructure of the white layer are studied with the aid of scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD). Therefore, the dry orthogonal cutting tests with worn tools were conducted to make the white layer first. The core issues, which this paper aims to reveal, are the transition of γ, γ′, γ' and δ phases and dynamic recrystallization mechanism within the white layer formed during turning Inconel 718. Nevertheless, the microstructure of the white layer is still not revealed clearly. White layer is commonly formed on the machined surface of nickel-based Inconel 718 superalloy, which probably induces the generation of cracks, leading to the fatigue life reduction of the workpieces.
