Morphological evolution of coherent misfitting precipitates in anisotropic elastic media

The shapes of coherent misfitting Ni₃Al precipitates were systematically investigated using a parameter {ζ} defined essentially by the ratio of particle sizes along 〈100〉 and 〈110〉. The variation of {ζ} with size was measured in several alloys using electron microscopy. {ζ} does not depend uniquely on particle size; it is also strongly influenced by the volume fraction of Ni₃Al. These results provide the first quantitative evidence that elastic interaction energy plays a major role not only in spatial correlations, but also in the morphological evolution of individual particles.