Joint microstructure and isothermal solidification modeling during transient liquid-phase bonding of a duplex stainless steel

An experimental investigation on transient liquid-phase bonding of a duplex stainless steel was carried by using Ni-based amorphous alloy as the interlayer.The microstructure of the bonded joint was observed with field emission scanning electron microscope(FE-SEM).The chemical compositions were analyzed by energy-dispersive X-ray spectroscopy(EDS) and wavelength-dispersive spectrometry(WDS).Phase structure of the bonded joint was identified by using X-ray diffraction(XRD).The results indicated that before the completion of isothermal solidification, the major secondary-phase precipitate present in the interface region between the insert and base alloy was BN.The dominating phases appeared in the interlayer zone were γ-Ni solid solution, Ni₃B and Cr-borides.Additionally, three diffusion models were employed to calculate the completion time of the isothermal solidification.By contrast to experimental results, the value obtained by solute distribution model was close to the actual value, and this model was considered to be suitable to the bonding process.