Structure and Properties of Eutectic Alloys

Abstract

Eutectic materials have become the subject of considerable interest and investigation in recent years from two separate standpoints. In the first place, the freezing behaviour of eutectic alloys has been investigated as a subject in its own right over the past fifteen years. During this same period of time the concepts of fibre-strengthening were developed and put to test. This led to the second wave of interest in eutectic alloys when it was shown that several simple binary eutectic alloys after unidirectional solidification exhibited tensile deformation characteristics typical of fibre-reinforced composites. Research on eutectic composites has divided naturally between the academic institutions on the one hand where a fundamental approach is taken with regard to the structure and properties of eutectic composites utilizing low temperature binary systems, and industrial or government research laboratories on the other hand where searches for commercial high temperature pseudo-binary eutectic composites are undertaken. In the former case, work has focused on solidification microstructures and their inherent structural defects, on the crystallographic orientation relationships between eutectic phases, and on detailed analyses of the mechanical behaviour of these simple eutectic composites. In the industrial and government establishments much of the work has been of an empirical nature with the aim of discovering commercially useful eutectic composites to replace the nickel-base super-alloys as high-temperature turbine materials. The present state of the art and science of the subject has been reported in the proceedings of the conference on ‘In-Situ Composites” in Lakeville, Connecticut. The second conference in this series takes place in September 1975.