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 du ring transient liquid-phase brazing with Ni-11 wt% P filler metal has been investigated. Single-crystal, coarse-grained and fine-grained nic kel base metal were brazed at 1150-degrees-C for various holding times . The eutectic width decreased linearly with the square-root of the br azing time in single-crystal, coarse-grained and fine-grained nickel b ase metals. The completion time for isothermal solidification decrease d 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 diff usion coefficient of phosphorus in solid nickel.