Point defects migration properties

Precipitates on grain boundaries can be a major factor in inhibiting grain growth, since the migration of a boundary is hampered when it is pinned by second-phase particles. Inclusions also affect the mechanical properties of the ceramic via interactions with dislocations and point defects, and precipitate stress fields may influence the further segregation of other species dissolved within the grains. 

The possible point-defect structures, migration properties,. . . are so numerous in intermetallic compounds that experiment alone cannot solve the problem. Unfortunately, theory here is still in its infancy. For example, the commonly used Miedema and bond-breaking semiempirical models to estimate point-defect formation energies are quite contradictory. It is only recently, since the 1980s, that more sophisticated theoretical methods have been developed and seem to be able to predict point-defect structures and properties with some accuracy. Great progress can be expected from the combined use of Monte-Carlo and molecular-dynamics simulations (Rey-Losada et al., 1993). 

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