Crystallites

Effects on material physical properties

If the individual crystallites are oriented completely at random, a large enough volume of polycrystalline material will be approximately isotropic. This property helps the simplifying assumptions of continuum mechanics to apply to real-world solids. However, most manufactured materials have some alignment to their crystallites, resulting in texture that must be taken into account for accurate predictions of their behavior and characteristics. When the crystallites are mostly ordered with a random spread of orientations, one has a mosaic crystal. Abnormal grain growth, where a small number of crystallites are significantly larger than the mean crystallite size, is commonly observed in diverse polycrystalline materials, and results in mechanical and optical properties that diverge from similar materials having a monodisperse crystallite size distribution with a similar mean crystallite size.