Structure design and experimental study on ultrasonic vibration–assisted induction brazing cubic boron nitride abrasive tools

Brazed superabrasive tool has been widely used in machining of difficult-to-cut materials to improve the machining efficiency and quality. However, the severe wear and associated short service life have to be faced for conventional induction brazed (CIB) abrasive tools during machining processes, owing to its weak bonding strength between abrasive grains and metal-bonded phases. In this case, the method of ultrasonic vibration–assisted induction brazing (UVAIB) was proposed to fabricate tools, through introducing ultrasonic vibration into brazing process to improve the abrasive bonding strength. Here, a novel UVAIB device was developed, and the geometric designation parameters were optimized using a finite element simulating method. In addition, the performance of UVAIB device was tested in terms of the impedance and amplitude. Subsequently, the comparative experiment trials were performed with the brazed abrasive tools under the CIB and UVAIB method. Results show that the ultrasonic energy loss of UVAIB device can be reduced, and then, the amplification value and vibration uniformity reach 8 and 92%, respectively. In addition, a large number of pores and macro-cracks inside tool’s metallic matrix for CIB can be observed, whereas the number of pores is reduced by 75%, and only fewer and smaller micro-cracks are found for UVAIB. Furthermore, compared with the grains’ intergranular fracture for CIB, UVAIB exhibits the transgranular fracture mode due to its higher bonding strength after adopting the ultrasonic vibrating method.