Work hardening mechanism based on molecular dynamics simulation in cutting Ni-Fe-Cr series of Ni-based alloy

In order to study the micro-forming mechanism of work hardening in cutting Ni-Fe-Cr series of Ni-based alloy using Cubic Boron Nitride (CBN) tool, the cutting model was established by means of molecular dynamics simulation analysis method. The Morse potential function and other potential functions were calculated to characterize the interaction between atoms. Then, the influence of variation of cutting force, the dislocation density, dislocation pile-up, Lomer-Cottrell dislocation, and solute atoms on work hardening are deeply analyzed. The results show that the metal surface with plastic deformation initiates a variety of internal mechanisms to hinder dislocation movement as dislocation density increases, dislocation motion and interaction between dislocations intensifies. The mechanism of work hardening in Ni-Fe-Cr alloy is not only dislocation pile-up that is not easy to slip or cannot slip or dislocation tangle caused by dislocation intersection, but also a lot of Lomer-Cottrell dislocations. The solute elements that reduce stacking fault energy indirectly affect the generation of Lomer-Cottrell dislocations. In addition, solute atoms in nickel-based alloys can pin dislocations, hinder the movement of dislocations, and promote dislocation tangle in the workpiece. Various mechanisms interact and influence each other, which is a complex whole. (C) 2019 Elsevier B.V. All rights reserved.