Boundary elastic strain energy

In general, the nuclei are not spherical. There are several reasons for this. One is that the a- 3 surface energy term, y p, depends on the orientations of the a and 3 phases. Another reason is that when nucleation occurs on oc-oc grain boundaries, the angle of contact, 0, between the a and 3 phases depends on the ratio of y p/yagb- A third reason is that the elastic strain energy is minimized if the precipitating phase is lenticular. 

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