The influence of base metal grain size on isothermal solidification during transient liquid-phase brazing of nickel

The influence of base metal grain size on isothermal solidification during transient liquid-phase brazing with Ni-11 wt% P filler metal has been investigated. Single-crystal, coarse-grained and fine-grained nickel base metal were brazed at 1150‡C for various holding times. The eutectic width decreased linearly with the square-root of the brazing time in single-crystal, coarse-grained and fine-grained nickel base metals. The completion time for isothermal solidification decreased in the order single-crystal, coarse-grained and fine-grained nickel base metal. The difference in isothermal solidification rates produced when brazing the different base metals is explained qualitatively by the influence of base metal grain boundaries on the apparent mean diffusion coefficient of phosphorus in solid nickel.