Microstructure of Bi–Cd–Pb ternary eutectic

Abstract

Specimens of the Bi–Cd–Pb ternary eutectic were solidified unidirectionally at very low speeds and quenched to form a representative solid/liquid interface for subsequent study. This eutectic was found to be of the Bi(faceted) –Cd(faceted)–Pb2Bi (non1aceted) type. A ‘double binary’ microstructure was formed on freezing, consisting of binary quasiregular regions composed of Bi and Pb₂Bi and binary regions of broken lamellar Cd–Pb₂Bi microstructure. Comparison with systems studied previously suggests that a faceted–faceted–non-faceted ternary eutectic of primarily lamellar form will tend to assume a double binary microstructure on freezing, the non-faceted phase will be common to the two binary structures, and each binary structure will take the form corresponding to that expected for a binary eutectic of similar volume fraction of faceting phase.

MST/3146