Novel experimental technique to observe equilibrated grain boundary groove shapes in opaque alloys

A new experimental method for determining solid/liquid and grain boundary energies in solid metal/liquid metal couples is suggested. The equilibrated grain boundary groove shapes in Zn-Al and Al-Cu binary alloys for the first time were observed from quenched sample with a Bridgman-type directional solidification apparatus. Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy for solid Zn solution, solid Al solution and solid CuAl2 have been determined from observed grain boundary groove shapes. A comparison of the experimental results obtained in this work with the values of Gibbs-Thomson coefficient, solid-liquid interface energy and grain boundary energy determined from observed grain boundary groove shapes with a radial heat flow apparatus in previous works was made for the same solid phases. It was seen that the present results are in good agreement with the values obtained in previous works. From these agreements, it can be concluded that a Bridgman-type directional solidification apparatus can be used to observe equilibrated grain boundary groove shapes. (C) 2008 Elsevier B.V. All rights reserved.