Determination of the Solid-Liquid Interface Energy in the Al-Cu-Ag System

The solid-liquid interface energy, σ _SL , is of major importance during phase transformation. It has a strong influence on solidification morphologies and the final grain structure. The “grain boundary groove in an applied temperature gradient” method developed by Gündüz et al.[6] was found to be suitable for measuring the solid-liquid interface energy in ternary alloy systems (e.g., Al-Cu-Ag). In order to measure the solid-liquid interface energy, a radial heat flow apparatus was constructed and assembled. This apparatus ensures a stable temperature gradient for hours and leads to grain boundary grooves in chemical equilibrium. After rapid quenching, the samples were metallographically prepared and the local curvature of the grooves was analyzed. To determine the interface energy, the Gibbs–Thomson equation was used, which requires the local curvature of the grain boundary grooves and the adherent local undercooling obtained from heat flux simulations on the scale of the grooves.