Abstract:   To study the surface generation mechanism of single-crystal nickel ultra-precision machining， a molecular dynamics simulation model of diamond cutting single-crystal nickel was established， and the influences of different parameters on single-crystal nickel nano machining were obtained through the analysis of the results. Then， the diamond cutting experiments were carried out on single-crystal nickels， and white light interferometer and scanning electron microscope were used to characterize the cutting surfaces and chip morphologies. The cutting parameters of single crystal nickels were optimized from both of theoretical and experimental. The results show that the cutting depth is positively related to the surface quality of single-crystal nickels in a certain range. The negative rake of the tool is conducive to the improvement of the surface quality， but it may bring burrs. Single-crystal nickels are not amorphous during diamond cutting processes. The type of dislocations is dominated by Shockley dislocations， and a small amount of Hirth， Stair-rod and Frank dislocations coexist. The ［1-10］ crystal direction of the （110） crystal plane has the smallest subsurface damage， which is the best crystal direction. The study may provide certain references for optimizing the ultra-precision machining technology and improving the machining accuracy of single-crystal nickels.

Key words: diamond cutting, single crystal nickel, molecular dynamics simulation, surface generation mechanism

摘要： 为研究单晶镍超精密切削加工表面生成机理，建立了金刚石切削单晶镍分子动力学仿真模型，通过结果分析得到不同参数对单晶镍纳米加工的影响；对单晶镍工件进行金刚石切削实验，采用白光干涉仪和扫描电子显微镜对切削表面和切屑形态进行表征，从理论和实验两方面对单晶镍切削加工工艺参数进行优化。研究结果表明：切削深度在一定范围内与单晶镍表面质量成正相关；刀具负前角有利于提高表面质量，但会带来毛刺；单晶镍在金刚石切削过程中未发生非晶化，位错类型以Shockley位错为主导，共存少量的Hirth、Stair-rod和Frank位错，（110）晶面的［1-10］晶向亚表面损伤最小，为最佳加工晶向。研究结果可为优化单晶镍的超精密加工工艺及提高加工精度提供一定参考。

关键词: 金刚石切削, 单晶镍, 分子动力学仿真, 表面生成机理