Experimental study on a two-dimensional ultrasonic vibration platform and milling of Ti2AlNb intermetallic alloy

In order to solve the problems of poor machining accuracy and surface quality of hard and brittle materials such as Ti2AlNb intermetallic alloy in conventional machining, the principle of apparent elasticity method was used to design a flat-plate vibration device. Firstly, the propagation characteristics of ultrasonic in inclined slot plate were analyzed by using the propagation law of acoustic wave in different media. Secondly, the vibration characteristics were analyzed and discussed in detail by using finite element software. Finally, the influence of the vibration characteristics of vibration platform on the cutting performance of Ti2AlNb alloy was studied through ultrasonic vibration cutting and common cutting (CC) experiments. The finite element modelling (FEM) and test results showed that when the slot width was 2 mm and the inclination angle was 45°, the vibration effect of the plate vibration device was the best, and the vertical upward vibration component was generated at the workpiece installation area of the plate. The errors between the measured frequency and the results of theoretical calculation and finite element analysis were 1.78% and 0.36%, respectively, which showed the reliability of finite element simulation. Compared with the three-dimensional ultrasonic vibration cutting (3DUVC) and CC, the results of two-dimensional ultrasonic vibration cutting (2DUVC) based on flat-plate vibration device showed an obvious “drainage tank” microstructure in variable speed cutting; when the rotating speed was 1700 r/min, the roughness value of 2DUVC was 54% and 57% lower than that of 3DUVC and CC, respectively. The amplitude along the feed direction was 8 μm, the surface roughness of 2DUVC decreased by 64% and 65.9%, respectively, compared with 3DUVC and CC. The number of chip sawtooth increased with the increase of ultrasonic amplitude and vibration dimension. The experimental results showed that for Ti2AlNb alloy, ultrasonic vibration cutting can obtain higher surface quality, and the two-dimensional ultrasonic vibration platform was helpful to improve the cutting performance of materials, and the 3DUVC can realize the rapid removal of materials.