Crystals habit, construction

Since the crystal shape, or habit, can be determined by kinetic and other nonequilibrium effects, an actud crystal may have faces that differ from those of the Wulff construction. For example, if a (100) plane is a stable or singular plane but by processing one produces a plane at a small angle to this, describable as an (xOO) plane, where x is a large number, the surface may decompose into a set of (100) steps and (010) risers [39]. 

One also encounters a similar system for two materials A and B which crystallize in different habits the construction of the corresponding phase diagram is indicated in Figure 3.8.14. This is handled by invoking two free-energy curves, a and 13 for the two different solid phases. Their intersections with Gi at various temperatures are similar to those of the preceding diagram. 

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