钛合金高速切削切屑形成机理的有限元分析

钛合金在切削加工时容易产生锯齿状切屑，周期性的锯齿状切屑会引起切削力高频波动，从而影响加工表面质量和刀具寿命。然而其切屑形成的机理尚无统一的结论。本研究采用刚塑性有限元模型以及正交化Cockroft—Latham断裂准则，对钛合金Ti6A14V高速正交切削进行了仿真。仿真结果显示，周期性断裂理论能很好地解释钛合金锯齿状切屑形成的机理，主剪切变形区应力状态的变化是裂纹萌生与扩展的主要原因。研究结论与相关试验切屑显微照片特征相吻合，可以为实现钛合金高速切削提供理论依据和技术支持。

Finite Element Analysis on the Chip Formation Mechanism of Titanium Alloy's High Speed Machining

Serrated chip may occur easily during machining titanium alloys.It will cause the periodical vibration of the cutting force,which may affect the surface integrity of the machined workpiece surface as well as tool life.However,there is no consensus on the titanium alloys' serrated chip formation mechanism.With a rigid visco-plastic model and normalized Cockroft and Latham separation criterion,orthogonal cutting process of titanium alloy Ti6Al4V at high speed is simulated.According to the results,it is verified that titanium alloys' chip formation can be explained well by the periodical crack theory and the changes of stress states in the primary shear zone are the main reason of crack's initiation and propagation.The result is correspondent with the chip micrograph of Ti6Al4V and can provide both theoretical and technical help for high speed machining of titanium alloys.