9. Structural morphology of alloys

It can be seen from the above that phase diagrams can be used to determine, under equilibrium or non-equilibrium conditions, the nature of the phases present in an alloy, and to some extent the distribution of these phases. However, structural morphology (shape, size, spatial distribution of phases) can often be estimated with the aid of phase diagrams, bearing in mind the following additional remarks concerning solidification and solid-state transformations.

On solidification, the primary solid phases often take the form of branched dendrites, or have a form related to the crystalline nature of the phases (e.g. lamellar graphite, angular-grained silicon). Alloys of eutectic composition consist, in the solid state, of two solid phases in the form of extremely fine grains, interlocked in a lamellar, globular or acicular arrangement, but the eutectic may be divorced....