Densification behavior in bonded interlayer of pulsed electric-current sintering bonding of oxide dispersion strengthened superalloys

The in-situ sintering bonding of Fe-base and Ni base ODS alloys was carried out using pulsed electric current sintering (PECS) technique. The mechanic al alloying powders with the same composition as base alloys were inserted between bonding specimens as an insert layer for PEGS bonding. Bonding cond itions were varied between 1023-1323 K for 0-5.4 ks applying the bonding pr essure of 30-70 MPa. The relative density in bonded interlayer was increase d with bonding temperature and holding time, finally attained to perfectly densificated. The densification of bonded interlayer was remarkably acceler ated by the bonding pressure while the densification is slightly accelerate d when the particle size insert powder decreases. The aspect ratio of prior particles in bonded interlayer increased with the lapse of holding time wh ereas the average size of it did not change so much through the bonding pro cess. The kinetics of densification of bonded interlayer during PEGS bondin g process could be expressed by two kinds of kinetic equation. It was eluci dated that the densification behavior of bonded interlayer during PEGS bond ing process was controlled by two sequential mechanisms of grain boundary d iffusion creep and diffusion.