Titanium alloy Ti6Al4V, an alpha-beta alloy, possesses many advantageous properties, such as high special strength, good resilience and resistance to high temperature and corrosion, fracture resistant characteristics and so on, being widely used in aerospace, biomedical and chemical industry. However, its machinability is still a challenge due to its low thermal conductivity, low elastic modulus and high chemical reactivity. As a novel and effective machining method, ultrasonic vibration assisted machining (UVAM) can effectively improve the machining performance of workpieces, which is widely used in the field of titanium alloy machining. A two-dimensional cutting finite element modeling methodology for orthogonal cutting titanium alloy Ti6Al4V was established to analyze the comparisons between conventional machining (CM) and ultrasonic vibration assisted machining and the effects of frequency and amplitude. The simulation results showed that (1) UVAM more easily formed serrated chip than that of CM. The chip segmentation coefficient GS which could quantitatively characterize the segmentation degree of chip showed an increasing trend with the increase of amplitude. (2) The cutting force curve of UVAM had periodic pulse fluctuation due to the effects of vibration in x-direction and y-direction. The main cutting force and the thrust force of UVAM showed the further decrease trend with the increase of frequency and x-direction amplitude. However, the y-direction amplitude made the contrary trend for the cutting force. (3) Meanwhile, with the increase of y-direction amplitude, the plastic and friction dissipation energies increased obviously. The introduction of ultrasonic vibration results in complex changes in the tool-chip contact, mechanical and temperature characteristics of the workpiece. Choosing the suitable vibration parameters will contribute to improving the machinability of titanium alloys.

钛合金Ti6Al4V是一种α-β合金，具有特殊强度高、回弹性好、耐高温、耐腐蚀、抗断裂等优点，广泛应用于航空航天、生物医学和化工等领域。然而，由于其低导热性、低弹性模量和高化学反应性，其可加工性仍然是一个挑战。超声波振动辅助加工（UVAM）作为一种新颖有效的加工方法，可以有效提高工件的加工性能，在钛合金加工领域得到广泛应用。建立正交切削钛合金Ti6Al4V二维切削有限元建模方法，分析常规加工(CM)与超声振动辅助加工的对比及频率和振幅的影响。仿真结果表明(1)UVAM比CM更容易形成锯齿状芯片。能够定量表征芯片分割程度的芯片分割系数GS随着振幅的增加呈增大趋势。(2) UVAM的切削力曲线受x方向和y方向振动的影响，具有周期性的脉冲波动。UVAM的主切削力和推力随着频率和x方向幅值的增加呈现进一步减小的趋势。然而，y 方向的振幅对切削力呈相反的趋势。(3) 同时，随着y方向振幅的增加，塑性和摩擦耗散能明显增加。超声波振动的引入导致工件的刀具-切屑接触、机械和温度特性发生复杂变化。选择合适的振动参数将有助于提高钛合金的切削加工性。