Fundamental aspects of ultrasonic assisted induction brazing of diamond onto 1045 steel

In this study, ultrasonic-assisted induction brazing (UAIB) of diamond grits onto 1045 steel with Ni–Cr–B–Si–Fe was investigated and compared with those obtained by the conventional induction brazing (CIB). Using UAIB led to the result that the surface of brazed filler alloy was flatter and less slags and the bond zone was of less and smaller cracks. The embedded ratio of brazed diamond was improved 35.4% by UAIB. Furthermore, UAIB-brazed joints contained a more even distribution and smaller grain sizes of interfacial microstructures. In both the methods studied, a layer of Cr3C2 was formed on the bonding interface; however, this layer was short and contained more discontinuous laths with random directions when UAIB was used. The maximum compressive residual stress at the bottom of the brazed diamond grits was reduced using UAIB by 21.6%. Using UAIB increased the average shear force of the joints by 28.5% and greatly reduced the percentage of fracture failure joints on the UAIB grinding wheel, suggesting an enhancement in the strength of the joints. These differences were ascribed to the acoustic effects induced by ultrasonic vibration.