Prediction of the maximal recalescence temperature upon rapid solidification of bulk undercooled CU70Ni30 alloy

Applying melt-fluxing, how to predict the maximal recalescence temperature T-R upon rapid solidification of bulk undercooled CU70Ni30 alloy has been investigated. Reproducible experimental results show that T-R decreases with the increase of the initial melting undercooling Delta T, and moreover its value is much lower, than that predicted by Level rule and Scheil equation, let alone the equilibrium liquidus temperature. Quantitative thermodynamic calculation, in combination with an analysis of solute distribution, demonstrates that, T-R is affected by the difference of Gibbs free energy between the residual liquid and solid after recalescence. Subjected to sufficiently high Delta T, T-R should be nearly equal to the thermodynamic T-o point corresponding to the concentration of the residual melt after recalescence. (C) 2008 Elsevier B.V. All rights reserved.