Introduction: Microstructure

Abstract

There is a very common observation that two nominally identical samples of a material may exhibit remarkably different properties. Such differences can often be traced back to how a material was synthesized or subsequently processed. If two materials have exactly the same composition, how can the properties be different? The answer is generally associated with heterogeneities in the material. These heterogeneities may be associated with spatial distributions of phases of different compositions and/or crystal structures, grains of different orientations, domains of different structural variants, domains of different electrical or magnetic polarizations, as well as of structural defects such as dislocations. Materials scientists routinely manipulate these inhomogeneities to optimize the properties of materials.