Nanocrystalline phases and epitaxial interface reactions during brazing of diamond grits with silver based Incusil-ABA alloy

The commercial active brazing alloy “Incusil-ABA” was used for the bonding of diamond grits in order to assess their suitability for high performance machining tools. It was found that the microstructure of the brazing alloy matrix consisted of primary precipitates of Cu in a Ag–Cu eutectic matrix and an additional Cu–In–Ti rich intermetallic phase. Interface characterisation revealed the presence of a Ti-rich interfacial layer between the diamond and the alloy matrix. Therefore, good wettability was obtained for the embedded diamond grit particles. This intervening layer comprised nanosized cuboidal TiC which seemed to have acted as a precursor to its formation and fine metastable needles that were identified as cubic Ti 3InC. Furthermore it was demonstrated that a three phase crystallographic orientation relationship had been obeyed at the interfacial region between the diamond, TiC and Ti 3InC.