The structure of the γ′ extended solid solution in a splat-cooled Ag-50 at.% Cu alloy

The structure of the γ′ extended solid solution in electron transparent areas of a splatcooled Ag-50 at.% Cu alloys was examined by transmission electron microscopy. This phase was usually found to be spinodally decomposed at large grain sizes (-1 μm in diameter), in contrast to X-ray diffraction data indicating that the γ′ solid solution was undecomposed. A solidification model for rapidly quenched eutectic alloys is proposed to account for the observed structure of the splat-cooled alloy. A transformation curve for the spinodal decomposition of γ′ is also calculated and related to predictions derived from the solidification model