Cutting force and surface finish are two critical characteristic parameters for diamond turned polycrystalline copper components. In this work, polycrystalline copper with different grain sizes achieved by friction stir processing (FSP) was machined by single point diamond turning. To accurately predict cutting force in diamond turning, a theoretical prediction model considering grain size of copper, Hall-Petch effect, and stress distribution on a diamond tool was developed. Three-direction cutting forces, i.e., principal cutting force, thrust force, and feed force, in the diamond turning process were calculated, respectively. To analyse the material microstructure and mechanical property, Electron Back Scattered Diffraction (EBSD), X-Ray Diffraction (XRD) and nano-indentation analysis were successively performed on the work material. Combing theoretical model and experimental results, the relationship between principal cutting force and thrust force on various processing parameters was successfully revealed. Furthermore, surface roughness of the copper work material processed by FSP is smaller than that without treatment. According to material analysis results, the combination of misorientation angle and Hall-Petch effect reduces the step height on diamond turned surface, which further contributes to a flatter diamond turned surface. Therefore, the combination of friction stir processing and single point diamond turning has the application potential to achieve a super-smooth surface finish in industry.

切削力和表面光洁度是金刚石车削多晶铜部件的两个关键特征参数。在这项工作中，通过单点金刚石车削加工通过搅拌摩擦加工 (FSP) 获得的不同晶粒尺寸的多晶铜。为了准确预测金刚石车削中的切削力，开发了一种考虑铜晶粒尺寸、霍尔-佩奇效应和金刚石刀具应力分布的理论预测模型。分别计算了金刚石车削过程中的三个方向切削力，即主切削力、推力和进给力。为了分析材料的微观结构和力学性能，对工作材料依次进行了电子背散射衍射（EBSD）、X射线衍射（XRD）和纳米压痕分析。结合理论模型和实验结果，成功揭示了主切削力和推力对各种加工参数的关系。此外，经过FSP处理的铜工件材料的表面粗糙度比未经处理的要小。根据材料分析结果，错取向角和霍尔-佩奇效应的结合降低了金刚石车削表面的台阶高度，这进一步有助于使金刚石车削表面更平坦。因此，搅拌摩擦加工和单点金刚石车削的结合在工业上具有实现超光滑表面光洁度的应用潜力。经FSP处理的铜工件材料表面粗糙度小于未经处理的铜工件材料。根据材料分析结果，错取向角和霍尔-佩奇效应的结合降低了金刚石车削表面的台阶高度，这进一步有助于使金刚石车削表面更平坦。因此，搅拌摩擦加工和单点金刚石车削的结合在工业上具有实现超光滑表面光洁度的应用潜力。经FSP处理的铜工件材料表面粗糙度小于未经处理的铜工件材料。根据材料分析结果，错取向角和霍尔-佩奇效应的结合降低了金刚石车削表面的台阶高度，这进一步有助于使金刚石车削表面更平坦。因此，搅拌摩擦加工和单点金刚石车削的结合在工业上具有实现超光滑表面光洁度的应用潜力。