The Characteristics Of Tool Wear Behavior Research In High-speed Turning Of Near αhigh Temperature Titanium Alloy BTi6431S

With the rapid development of aviation industry, the demands of the material thermostable performance were more and more. BTi6431 S is a near α high temperature titanium alloy of the latest development, it under the environment of600℃ still have the very yield strength and creep resistance. And it in the field of aerospace have vast application prospect. But titanium alloy is the typical difficult machining material, the most study now mainly is machining titanium alloy Ti6Al4 V,and the literature of near α titanium alloy BTi6431 S machinability have not been observed. Therefore, this article is that test the near α titanium alloy BTi6431 S by high-speed turning and systematic research the chip morphology characteristics,cutting force and wear mechanism of tool in machining titanium alloy BTi6431 S.That the chip morphology of titanium alloy BTi6431 S is typical saw-tooth chip is found by analyzed the chip morphology of titanium alloy BTi6431 S. With cutting speed increasing, the height of tooth increase, frequency rise and serration is more significant. Measured and analyzed the geometrical characteristics of chip, the shear band inclination reduce and the segmentation degree increase when cutting speed or feed rate increasing, and the segmentation degree of titanium alloy BTi6431 S significantly higher than the segmentation degree of titanium alloy Ti6Al4 V. Besides,the microstructure evolution of the adiabatic shear zone of the chip also is analyzed.The result shows that deformation band gradually transformed into transformed band in shear band when cutting speed increasing.Analyzed the change rule of cutting force, the results shows cutting force increase when cutting speed or feed rate increasing, and the impact of cutting force Fy is the biggest and Fx and Fz is smaller at the change of cutting parameter. In addition, the average cutting force gradually increase and the fluctuation range of cutting force rise when tool wearing. And the cutting force in cutting titanium alloy BTi6431 S is higher than in cutting titanium alloy Ti6Al4 V.Analyzed the tool wear morphology, the results shows that the collapse phenomenon of tool cutting edge in machining titanium alloy BTi6431 S is severe than machining titanium alloy Ti6Al4 V. Using SEM and EDS measurement, the Ti,Al, Sn elements of work-piece material is found in the cutting edge area and the Co and W elements do not exist and The O elements exist in the wear area boundary.This explains that the tool wear mainly is the generated result under adhesive,oxidative and diffusive. In addition, under the same cutting length, when cutting speed is 90m/min, the wearing capacity of tool flank face in machining titanium alloy BTi6431 S is 0.317 mm and in machining titanium alloy Ti6Al4 V is 0.187 mm. This indicates that the tool wear in machining titanium alloy BTi6431 S is severe.According to ultrasonic elliptic vibration theory, the winding chip is observed by ultrasonic elliptic vibration high-speed cutting on machining titanium alloy BTi6431 S,this reason is the continuous change of tool geometric angle in machining. And ultrasonic elliptical vibration enables fluctuation range of cutting force to decrease50% and make cutting system stable. In addition, the tool durability is enhanced in ultrasonic elliptic vibration high-speed cutting and the removal volume of cutting material added.