Nickel based single crystal alloys have excellent properties such as heat resistance, corrosion resistance and creep resistance, which are widely used in aerospace and other national defense fields. Severe work hardening occurs in the process of cutting nickel based single crystal alloy. How to improve the machining quality and grasp the cutting deformation mechanism has become the research focus. In this paper, the effect of work hardening on the surface of workpiece during the atomic and close-to-atomic scale (ACS) cutting process is studied. The model of $S{i}_3{N}_4$ ceramic tool cutting the nickel based single crystal alloy was established, and the ACS cutting process was simulated by the molecular dynamics method. The existing strain rate conversion model was modified to make it suitable for the process of ACS cutting into nano compression with the same strain rate. The results show that the dislocation density of Ni-based single crystal alloy workpiece changes greatly with the change of cutting distance. According to the change of microstructure in the workpiece, a new staged work hardening mechanism is proposed. The development of work hardening in the cutting process is divided into three stages, and the transition node of each hardening stage is defined. An important sign of the transformation from the first stage to the second stage of work hardening is the occurrence of a large number of dislocation pile-up group, dislocation tangles and the appearance of non-basal slip lines. The distinctive feature of the transformation from the second stage to the third stage of work hardening is that a large number of screw dislocations are cross-slip and the dislocation pile-up group is destroyed. At the same time, the different hardening mechanisms in each stage and the reasons for the change of work hardening mechanism in different stages are summarized. The research content is believed to be helpful to understand the mechanism of significant work hardening effect in nickel-based alloys.

镍基单晶合金具有优异的性能，例如耐热性，耐腐蚀性和抗蠕变性，广泛用于航空航天和其他国防领域。在切割镍基单晶合金的过程中会发生严重的加工硬化。如何提高加工质量并掌握切削变形机理已成为研究的重点。本文研究了在原子和接近原子尺度（ACS）切削过程中工件表面淬火对工件表面的影响。的型号$\mathrm{小号}{\mathrm{一世}}_3{ñ}_4$建立了镍基单晶合金的陶瓷切削刀具，并通过分子动力学方法模拟了ACS切削过程。对现有的应变率转换模型进行了修改，使其适用于以相同的应变率将ACS切成纳米压缩的过程。结果表明，Ni基单晶合金工件的位错密度随切削距离的变化而变化很大。根据工件微观组织的变化，提出了一种新的分阶段工作硬化机制。切削过程中工件硬化的发展分为三个阶段，并定义了每个硬化阶段的过渡节点。从工作硬化的第一阶段到第二阶段转变的一个重要标志是，出现了大量的位错堆积组，位错缠结和出现了非基底滑移线。从工作硬化的第二阶段到第三阶段的转变的显着特征是，大量的螺钉错位交叉滑动，并且错位堆积组被破坏。同时，总结了每个阶段不同的硬化机制，以及不同阶段工作硬化机制发生变化的原因。认为该研究内容有助于理解镍基合金中显着的加工硬化作用的机理。从工作硬化的第二阶段到第三阶段的转变的显着特征是，大量的螺钉错位交叉滑动，并且错位堆积组被破坏。同时，总结了每个阶段不同的硬化机制，以及不同阶段工作硬化机制发生变化的原因。认为该研究内容有助于理解镍基合金中显着的加工硬化作用的机理。从工作硬化的第二阶段到第三阶段的转变的显着特征是，大量的螺钉错位交叉滑动，并且错位堆积组被破坏。同时，总结了每个阶段不同的硬化机制，以及不同阶段工作硬化机制发生变化的原因。认为该研究内容有助于理解镍基合金中显着的加工硬化作用的机理。