Transient liquid-phase bonding in the Ni-Al-B system

Transient liquid-phase (TLP) bonding experiments were performed using a Ni- 10.3 at, pet Al alloy and a Ni-10 at. pet B filler material, and the result s were compared to simulations performed using the finite-difference diffus ion code, DICTRA. For the simulations, a thermodynamic assessment of the Ni -Al-B system was used to define the phase diagram and the thermodynamic fac tors of the diffusion coefficients. Composition-dependent diffusion mobilit ies were assessed for the ternary system. Predicted liquid widths as functi ons of time were in good agreement with the experiments. The calculated and experimental Al composition profiles agree in the matrix but not in the li quid. The simulations qualitatively predicted the observed precipitation an d later dissolution of the intermetallic tau -phase (Ni20Al3B6) in the base material. This research demonstrated the potential for modeling the format ion of spurious phases during TLP bonding of practical superalloy systems.