Galvanized surface with visible crystallites of zinc. Crystallites in the steel under the coating are microscopic.

A crystallite is a domain of solid-state matter that has the same structure as a single crystal. Image:Galvanized surface. ... Image:Galvanized surface. ... Galvanization refers to any of several electrochemical processes named after the Italian scientist Luigi Galvani. ... General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ...

Solid objects that are large enough to see and handle are rarely composed of a single crystal, except for a few cases (gems, silicon single crystals for the electronics industry, certain types of fiber, and single crystals of a nickel-based superalloy for turbojet engines). Most materials are polycrystalline; they are made of a large number of single crystals—crystallites—held together by thin layers of amorphous solid. The crystallite size can vary from a few nanometers to several millimeters. A single crystal is a crystalline solid in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample. ... A gemstone is a mineral, rock (as in lapis lazuli) or petrified material that when cut or faceted and polished is collectible or can be used in jewellery. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... Fiber (American English) or fibre (Commonwealth English) is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to pieces of thread. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... Jet engine diagram Turbojets are the simplest and oldest kind of general purpose jet engine. ... An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. ... The metre (or meter) (symbol: m) is the SI base unit of length. ...

If the individual crystallites are oriented randomly (that is, if they lack texture), a large enough volume of polycrystalline material will be approximately isotropic. This propery helps the simplifying assumptions of continuum mechanics to hold in real-world solids. However, most manufactured materials have some alignment to their crystallites, which must be taken into account for accurate predictions. In materials science, texture is the property of a materials individual crystallites having nonrandom orientation. ... Isotropic means independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. ... -1...

Metallurgists often refer to crystallites as "grains"; thus fracture can be an intergranular fracture or a transgranular fracture. But there is an ambiguity with powder grains: a powder grain can be made of several crystallites. Thus, the (powder) "grain size" found by laser granulometry can be different from the "grain size" (in fact: crystallite size) found by X-ray diffraction (e.g. Scherrer method), by optical microscopy under polarised light or by scanning electron microscopy (backscattered electrons). Metallurgy is a domain of materials science and of materials engineering that studies the physical and chemical behavior of metallic elements and their mixtures, which are called alloys. ... For fractures in bones, see Fracture (bone). ... An intergranular fracture is a fracture that follows the edges of latices in a granular material, ignoring the grains in the individual latices. ... A Transgranular fracture is a fracture that follows the grains of the material. ... X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of X-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ... Microscopy is any technique for producing visible images of structures or details too small to otherwise be seen by the human eye, using a microscope or other magnification tool. ... Low temperature SEM magnification series for a snow crystal. ...

Grain boundaries

Although the term "crystallite" is more precise, the boundary between two crystallites is traditionally known as a grain boundary. The term "crystallite boundary" is rarely used, and the fact that powder grains are not attached to one another and so do not form boundaries helps to remove ambiguity in this case.

Grain boundaries disrupt the motion of dislocations through a material; reducing crystallite size is therefore a common way to improve strength, often without any sacrifice in toughness. The high interfacial energy and relatively weak bonding in grain boundaries makes them preferred sites for the onset of corrosion and for the precipitation of new phases from the solid. They are also important to many of the mechanisms of creep. For the syntaxic operation, see Dislocation (syntax) For the medical term, see Dislocation (medicine) In materials science a dislocation is a linear crystallographic defect, or irregularity, in crystal structure. ... Strength may refer to Physical strength of organisms means (especially the muscles of most metazoa) of locomotion and movement Strength of materials in physics, engineering and materials science Strength is a rap compilation presented by Asiatic Warriors Strength (VIII) is a Major Arcana card in Tarot. ... Toughness, in material science and metallurgy, is the resistance to fracture of a material when suddenly stressed. ... Surface energy quantifies the disruption of chemical bonds that occurs when a surface is created. ... Corrosion, atmospheric and biologic (Barnacles) Corrosion is deterioration of useful properties in a material due to reactions with its environment. ... Creep is the term given to the material deformation that occurs as a result of long term exposure to levels of stress that are below the yield or ultimate strength. ...

Grain boundaries are generally only a few nanometers wide. In common materials, crystallites are large enough that grain boundaries account for a small fraction of the material. However, very small grain sizes are achievable. In nanocrystalline solids, grain boundaries become a significant volume fraction of the material, with profound effects on such properties as diffusion and plasticity. In the limit of small crystallites, the volume fraction of grain boundaries approaches 100%, the material ceases to have any crystalline character, and becomes an amorphous solid. Diffusion, being the spontaneous spreading of matter (particles), heat, or momentum, is one type of transport phenomena. ... In physics and materials science, plasticity is a property of a material to undergo a non-reversible change of shape in response to an applied force. ... An amorphous solid is a solid in which there is no long-range order of the positions of the atoms. ...

Generally, polycrystals cannot be superheated; they will melt promptly once they are brought to a high enough temperature. This is because grain boundaries are amorphous, and serve as a nucleation point for the liquid phase. By contrast, if no solid nucleus is present as a liquid cools, it tends to become supercooled. Since this is undesirable for mechanical materials, alloy designers often take steps against it. See grain refinement. In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... Supercooling is the process of chilling a liquid below its freezing point, without it becoming solid. ... An alloy is a combination, either in solution or compound, of two or more elements, which has a combination of at least one metal, and where the resultant material has metallic properties. ... Grain refinement is a set of techniques used in metallurgy to ensure that the crystallites (grains) that make up a metallic object are sufficiently small. ...

See also

• Crystal
• Crystallography