Atomic-scale study of the nano-cutting deformation mechanism of nickel-based single crystal superalloy containing Cr, Co, and γ/γ´

To study the cutting micromechanics of nickel-based single crystal superalloy containing γ/γ´ two-phase structures and strengthening elements, a molecular dynamics method was used to establish a cutting model for nickel-based single crystal superalloy. The variation of machining force, shear strain, atomic displacement, and surface quality were analyzed in depth, and the effect of strengthening element content in the γ phase on the cutting behavior was investigated by comparing different models. It was found that the dislocation tangle is easily formed in the γ phase of nickel-based single crystal superalloy leading to increased machining forces, in addition, the coherent interface is stronger and can block the development of shear strain zones and the displacement of atoms. It is also found that the elastic recovery of γ phase is lower than that of γ´ phase, resulting in the deepest part of the machined surface always appearing in γ phase. Finally, by studying the influence of the content of strengthening elements on the material, it is found that the strengthening elements Cr and Co in γ phase can promote the generation of dislocation tangle, and also enhance the strength of γ phase and coherent interface and improve the deformation resistance of the workpiece.