In micro-cutting, microstructure induced anisotropic properties highly affect the machinability of materials because the removal amount is almost on same level as the size of microstructures such as grains and phases. In this paper, cutting force fluctuation induced by different phases is theoretically and experimentally investigated in the micro-cutting of dual-phase Ti6Al4V alloy. Particularly, a significant change of cutting force was observed as the tool traverses phase boundaries. Furthermore, the mechanism of the variation of cutting forces is discussed from perspectives of crystallographic orientation, critical resolved shear stresses and slip systems. Constitutive model and geometrical relationship between the tool and workpiece are also proposed to analyzed the resolved shear stresses of phases with different crystallographic orientations. The results agree well with experimental data, indicating that activation of various slip systems is directly determined by the values of corresponding resolved shear stresses. Additionally, cutting force fluctuation is primarily attributed to the change of slip systems at phase boundaries in the micro-cutting. The main findings of this study present the significant role of crystallographic orientations and slip systems in governing cutting force fluctuations at phases and phase boundaries, which provide valuable insights for optimization of cutting parameters in machining of titanium alloys.

中文翻译：

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Ti6Al4V 合金正交微切削中相边界效应对切削力波动的影响研究


在微切削中，微观结构诱导的各向异性特性对材料的可加工性影响很大，因为去除量几乎与晶粒和相等微观结构的尺寸处于同一水平。本文从理论和实验的角度研究了双相 Ti6Al4V 合金微切削中不同相引起的切削力波动。特别是，当刀具穿过相界时，观察到切削力的显着变化。此外，从晶体取向、临界分辨剪切应力和滑移系统的角度讨论了切削力变化的机制。还提出了本构模型和刀具与工件之间的几何关系，以分析具有不同晶体取向的相的分辨剪切应力。结果与实验数据非常吻合，表明各种滑移系统的激活直接由相应的已解析剪切应力的值决定。此外，切削力波动主要归因于微切削中相边界处滑移系统的变化。本研究的主要发现揭示了晶体取向和滑移系统在控制相和相界切削力波动中的重要作用，这为钛合金加工中切削参数的优化提供了有价值的见解。