Abstract: As a difficult-to-machine metal material, the application range of tungsten heavy alloy has been limited by its ultra-precision processing level. Ultrasonic elliptical vibration cutting technology has great application prospects in ultra-precision cutting of tungsten heavy alloy. Through the study of cutting removal mechanism, it can promote its application in the field of ultra-precision cutting of tungsten heavy alloy. Therefore, firstly, the ultrasonic elliptical vibration cutting trajectory is analyzed. Combined with the instantaneous shear angle change, the ultrasonic elliptical vibration cutting bending moment and cutting force model are established. Based on the above model, the ultrasonic elliptical vibration cutting characteristics are analyzed by comparing with conventional cutting. Then, the ultrasonic elliptical vibration scratching experiment and cutting experiment of tungsten heavy alloy are carried out by using single crystal diamond tool. The plastic embrittlement characteristics, chip thickness and residual stress of cutting surface are detected and analyzed by SEM, white light confocal microscope, X-ray residual stress analyzer and other equipment. Theoretical analysis and cutting experiments show that compared with conventional turning, the material removal scale under ultrasonic elliptical vibration cutting is reduced from micron to nanometer, and the tungsten heavy alloy exhibits stronger plasticity. With the change of shear angle, ultrasonic elliptical vibration cutting will produce greater downward force in the process of material removal, leaving greater residual stress on the cutting surface. Under ultrasonic elliptical vibration cutting, the cutting direction is more consistent with the material fracture direction. Combined with the sharp single crystal diamond tool, it is beneficial to realize the ultra-precision cutting of tungsten heavy alloy.

Key words: tungsten heavy alloy, ultrasonic elliptical vibration cutting, single-crystal diamond cutters, cutting bending moment