Interface kinetics of combustion–diffusion bonding of Ni3Al/Ni and TiAl/Ti under direct current field

The bonding of TiB2–Ni and TiC–Ni composites to, respectively, Ni and Ti substrates was investigated by field-activated and pressure-assisted synthesis. Bonding and in situ synthesis was utilized to prepare (TiB2)pNi/Ni3Al/Ni (Composition 1) and (TiC)pNi/TiAl/Ti (Composition 2) joining structures. The effect of applied current on the kinetics of formation of the diffusion layer between the substrate (Ni or Ti) and the respective intermetallic layer (Ni3Al or TiAl) was investigated. For both compositions, the current was shown to have a marked influence of the activation energy of formation of the layer, decreasing it by as much as 31 %. Calculations of adiabatic temperatures suggest a possible current contribution to interdiffusion, as has been reported previously.