Study of the structure of metals and alloys, particularly using microscopic and X-ray diffraction techniques. Visual and optical microscopic observation of metal surfaces and fractures can reveal valuable information about the crystalline, chemical, and mechanical makeup of the material. In electron microscopes a beam of electrons instead of a beam of light is directed onto the specimen. The development of transmission electron microscopes has made it possible to examine internal details of very thin metal foils. X-ray diffraction techniques are used to study phenomena related to the grouping of the atoms themselves. See alsomaterials science, Henry C. Sorby.