Solid-liquid interfacial energy of Al-Zn solid-solutions in equilibrium with Al-Zn liquid

Abstract

The grain boundary groove method has been successfully used to measure solid-liquid interfacial energies, σSL, experimentally for binary eutectic and peritectic systems, multi-component systems as well as pure materials and for opaque materials as well as transparent materials. It was shown that the grain boundary groove method can be use to obtain σSL for any alloy system provided that the prepared alloy sample can be held at the evaluated temperature for a long enough time with a very stable temperature gradient. In order to show the applicability of the groove method to any system, a part of the Al-Zn phase diagram was chosen. Equilibrated grain boundary groove shapes for solid Alα solution (Al-30wt%Zn) in equilibrium with AlZn liquid (Al-60wt%Zn) have been directly observed with a radial heat flow apparatus. The Gibbs-Thomson coefficient, Γ, was determined with a numerical method using observed groove shapes. The measured thermal conductivities of the solid Alα solution and AlZn liquid phases and the temperature gradient in the solid phase at the solid-liquid interface were used for the calculation of Γ and then σSL was determined using the Gibbs-Thomson equation. The grain boundary energy for the same system was also obtained from the observed groove shapes. The results of the work were compared with the results of the related experimental works.