Phase transformations, plane front

Nonuniform composition occurs not only in a linear plane front solidification process, but can occur in almost any nucleation-and-growth processes (solid/liquid or solid/solid). In such cases, compositional partitioning between the growing nuclei and the parent matrix phase leads to a characteristic cored microstructure, as shown in Figure 6.33. Coring can have undesirable effects on materials properties, and so it is often removed by heat treating the microstructure at a temperature just below the transformation temperature to allow solid-state diffusion to homogenize the composition. 

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