<P> The resulting solid macrostructure from a eutectic reaction depends on a few factors . The most important factor is how the two solid solutions nucleate and grow . The most common structure is a lamellar structure, but other possible structures include rodlike, globular, and acicular . </P> <P> Compositions of eutectic systems that are not at the eutectic composition can be classified as hypoeutectic or hypereutectic . Hypoeutectic compositions are those with a smaller percent composition of species β and a greater composition of species α than the eutectic composition (E) while hypereutectic solutions are characterized as those with a higher composition of species β and a lower composition of species α than the eutectic composition . As the temperature of a non-eutectic composition is lowered the liquid mixture will precipitate one component of the mixture before the other . In a hypereutectic solution, there will be a proeutectoid phase of species β whereas a hypoeutectic solution will have a proeutectic α phase . </P> <P> Eutectic alloys have two or more materials and have a eutectic composition . When a non-eutectic alloy solidifies, its components solidify at different temperatures, exhibiting a plastic melting range . Conversely, when a well - mixed, eutectic alloy melts, it does so at a single, sharp temperature . The various phase transformations that occur during the solidification of a particular alloy composition can be understood by drawing a vertical line from the liquid phase to the solid phase on the phase diagram for that alloy . </P> <P> Some uses include: </P>

What is the composition of alpha at the eutectic temperature