Abstract Ultrasonic vibration has received widespread attention for its dramatic effect on grain refinement and microstructure modification during casting, additive manufacturing, cold rolling, and cutting, changes which can significantly improve the mechanical and physical properties of components. As a novel ultrasonic vibration cutting method, rotary ultrasonic elliptical milling (RUEM) has been introduced to mill the alloy Ti-6Al-4V. However, the effects of ultrasonic elliptical vibration on the microstructures of machined surfaces in end milling of Ti-6Al-4V are still unclear. A comprehensive study on the surface characteristics and sub-surface microstructure in RUEM of Ti-6Al-4V was conducted. The results show that the uniform textures, in the form of ridges mapped on the machined surface in RUEM, varied with the cutting speed. Compared with conventional milling, microchip debris adhesion on the machined surface was significantly reduced by using RUEM. Moreover, intense plastic deformation in the sub-surface was obtained, and nanocrystalline layers, with grain dimensions of 10 nm to 100 nm, were fabricated on the processed surfaces of RUEM. Additionally, the improvement in sub-surface microstructure increased the surface micro-hardness from 21.22% to 33.84%. This study allows an in-depth understanding of sub-surface deformation and surface nanocrystallization in RUEM of Ti–6Al–4V.

中文翻译：

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Ti-6Al-4V旋转超声椭圆端铣的表面和亚表面分析

摘要 超声振动在铸造、增材制造、冷轧和切削加工过程中对晶粒细化和微观结构改变具有显着影响，可显着改善部件的机械和物理性能，因此受到广泛关注。作为一种新型的超声振动切割方法，已经引入旋转超声椭圆铣削（RUEM）来铣削Ti-6Al-4V合金。然而，超声椭圆振动对Ti-6Al-4V端铣加工表面微观结构的影响仍不清楚。对 Ti-6Al-4V 的 RUEM 表面特征和亚表面微观结构进行了综合研究。结果表明，在 RUEM 中，以映射在加工表面上的脊线形式的均匀纹理随切削速度而变化。与传统铣削相比，使用 RUEM 显着减少了加工表面上的微芯片碎片粘附。此外，在亚表面获得了强烈的塑性变形，并且在 RUEM 的加工表面上制造了晶粒尺寸为 10 nm 至 100 nm 的纳米晶层。此外，亚表面微观结构的改善使表面显微硬度从 21.22% 增加到 33.84%。这项研究可以深入了解 Ti-6Al-4V RUEM 中的亚表面变形和表面纳米化。在 RUEM 的加工表面上制造。此外，亚表面微观结构的改善使表面显微硬度从 21.22% 增加到 33.84%。这项研究可以深入了解 Ti-6Al-4V RUEM 中的亚表面变形和表面纳米化。在 RUEM 的加工表面上制造。此外，亚表面微观结构的改善使表面显微硬度从 21.22% 增加到 33.84%。这项研究可以深入了解 Ti-6Al-4V RUEM 中的亚表面变形和表面纳米化。