Finite element and experimental analysis of grain refinement caused by dynamic recrystallization during high-speed cutting of nickel-based superalloys

Nickel-based superalloys are subjected to complex mechanical and thermal loads during high-speed cutting, resulting in dynamic recrystallization behavior. The microstructure state is closely related to fatigue performance. In this paper, the Johnson-Mehl-Avrami-Kolmogorov model is used to predict the microstructure evolution of during high-speed cutting of superalloy GH4169. The finite element model of microstructure evolution considering dynamic recrystallization is established by user-defined subroutine on simulation platform. The error of cutting force obtained by experiment and simulation is within 12%. Serrated chips are obtained in high-speed cutting of superalloy GH4169. The typical characteristics of serrated chips such as peak, valley and peak-to-peak distance obtained by simulation are used to compare with the experimental results, and the error is within 20%. The dynamic recrystallization grain size increases as cutting speed increases. The promoting effect of increasing temperature on grain growth is greater than that inhibition effect of increasing strain rate, which leads to the increase of average grain size of machined surface.