Brittle-to-ductile transition in elliptical vibration-assisted diamond cutting of reaction-bonded silicon carbide

Synergetic deformation behavior between different phases has a strongly impact on machining characteristics of composites. In the present work, we investigate ultrasonic elliptical vibration-assisted diamond cutting of reaction-bonded silicon carbide (RB-SiC) by using finite element simulations and corresponding experimental validations. In particular, a specific-cutting-energy-based criterion, considering both the material composition of two phases and the cutting tool trajectory of two-dimensional vibrations, is established to quantitatively characterize the brittle-to-ductile transition of RB-SiC. The predicted value of the critical depth of cut for the brittle-to-ductile transition of RB-SiC by finite element simulations agrees well with that derived from diamond grooving experiment. Simulation results reveal that the synergetic deformation behavior between SiC matrix and Si particle substantially affects machining results of RB-SiC, and is greatly dependent on the cutting tool trajectory. Specifically, both finite element simulations and experiments demonstrate that the ductile machinability of RB-SiC can be significantly enhanced by applying ultrasonic elliptical vibration-assisted cutting, as compared to ordinary cutting.