Prediction of the metamorphic layer in ultrasonic vibration-assisted cutting of GH4169

The nickel-based superalloy GH4169 is widely used in key structural components such as aircraft engines due to its excellent high-temperature strength and corrosion resistance. However, in traditional cutting processes, the surface layer is prone to forming a metamorphic layer under thermal mechanical coupling, which in turn affects the fatigue life and service reliability of the parts. To achieve accurate prediction of metamorphic layer thickness, this paper constructs a multi physics coupled model considering instantaneous cutting thickness changes, shear angle evolution, and non-uniform stress-strain distribution based on the Cattaneo–Vernotte non-Fourier heat conduction model. The model uses the dynamic recrystallization starting temperature as a criterion to achieve theoretical calculation of the thickness of the metamorphic layer. By conducting dry cutting experiments under different cutting speeds, the prediction accuracy of the model was verified. The results showed that the model can accurately reflect the influence of speed changes on the thickness of the metamorphic layer, and the prediction error is controlled within 5%.