Microstructures of Directionally Solidified Al–Ag–Cu Ternary Eutectics

Abstract

Different three-phase microstructures are observed in directionally solidified Al–Ag–Cu ternary eutectics composed of an Ag2Al, an Al2Cu and a solid solution α-Al phase. A survey from regular to irregular structures is given and some special, new structural defects are observed and discussed. An approach for the quantitative description of the rich variety of complex three-phase microstructures is suggested including the defects. Shape factor and specific surface area of the phase particles are determined and compared for different microstructures.