Residual stress prediction in axial ultrasonic vibration–assisted milling in situ TiB₂/7050Al MMCs

As a new method developed for machining difficult-to-cut materials, ultrasonic vibration–assisted machining technology not only could be effective in reducing cutting force and temperature but also could be significant in obtaining residual compressive stress. Especially, residual compressive stress is essential to realize anti-fatigue manufacturing for components. However, in recent years, research on residual stresses of ultrasonic vibration–assisted machining mainly focuses on experimental and finite element analysis methods. In this paper, an analytical model was established by considering the effect of ultrasonic vibration to predict residual stresses and reveal the mechanism for UVM of in situ TiB₂/Al-MMCs. And a series of experiments were conducted to verify the residual stress model proposed and analyze the effect of ultrasonic vibration and cutting parameters on the surface residual stress. The results show that the predicted residual stresses are in good agreement with measured residual stress. Cutting parameters have a significant effect on the surface residual stress by influencing cutting force and cutting temperature. Residual compressive stresses could be achieved in both UVM and conventional milling, and residual compressive stresses in the former are larger than that in the latter. With cutting speed and cutting depth increasing, the relative increase ratio between UVM, and CM decreased gradually, while with feed rate increasing, it increased first and then decreased slightly.