Mapping the microstructure evolution of nickel deformed by orthogonal cutting

Abstract Severe plastic deformation prompted by orthogonal cutting is used to create deformed microstructures in commercially pure nickel machined under multiple cutting conditions. The resulting thermomechanical conditions, strain, strain rate, and temperature rise are calculated resulting in the final microstructure of the chip. The microstructure response is quantified for the generated defect during deformation, i.e. dislocation densities besides the microhardness. The dislocation density is measured using the X-ray diffraction peak broadening implementing the Williamson–Hall, and Williamson–Smallman methods. The microstructural consequences are examined through creating the rate-strain-microstructure (RSM) mappings using the Zener-Hollomon (Z) parameter. A 2D visualization of the microstructure response is acquired, and the effects of the strain and Ln(Z) on the measured dislocation densities and microhardness are discussed. The microstructural consequences are validated with the microstructure results reported in the literature over a wide range of Ln(Z) involving temperatures in the range from room temperature to 1420K.