MORPHOLOGICAL EVOLUTION OF COHERENT MISFITTING PRECIPITATES IN ANISOTROPIC ELASTIC MEDIA

The shapes of coherent misfitting Ni3Al precipitates were systematically investigated using a parameter zeta defined essentially by the ratio of particle sizes along [100] and [110]. The variation of zeta with size was measured in several alloys using electron microscopy. Zeta 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.