Material removal mechanisms in ultrasonic vibration-assisted high-efficiency deep grinding γ-TiAl alloy

Gamma titanium-aluminum intermetallic compounds (γ-TiAl) have gained considerable attentions in the aerospace industry due to their exceptional thermal resilience and comprehensive attributes, making them a prime example of lightweight and advanced materials. To address the frequent occurrence of burns and severe tool deterioration during the process of high-efficiency deep grinding (HEDG) on γ-TiAl alloys, ultrasonic vibration-assisted high-efficiency deep grinding (UVHEDG) has been emerged. Results indicate that in UVHEDG, the grinding temperature is on average 15.4% lower than HEDG due to the employment of ultrasonic vibrations, enhancing coolant penetration into the grinding area and thus reducing heat generation. Besides, UVHEDG possesses superior performance in terms of grinding forces compared to HEDG. As the material removal volume (MRV) increases, the tangential grinding force (F_t) and normal grinding force (F_n) of UVHEDG increase but to a lesser extent than in HEDG, with an average reduction of 16.25% and 14.7%, respectively. UVHEDG primarily experiences microfracture of grains, whereas HEDG undergoes large-scale wear later in the process due to increased grinding forces. The surface roughness (R_a) characteristics of UVHEDG are superior, with the average value of R_a decreasing by 46.5% compared to HEDG as MRV increases. The surface morphology in UVHEDG exhibits enhanced smoothness and a shallower layer of plastic deformation. Grinding chips generated by UVHEDG show a more shear-like shape, with the applied influence of ultrasonic vibration on chip morphology, thereby impacting material removal behaviors. These aforementioned findings contribute to enhanced machining efficiency and product quality of γ-TiAl alloys after employing ultrasonic vibrations into HEDG.