Crystallite

polycrystallinegraingrainspolycrystalcrystallitesgrain boundariesgrain structuregrain sizepolycrystalsmulticrystalline
A crystallite is a small or even microscopic crystal which forms, for example, during the cooling of many materials.wikipedia
245 Related Articles

Texture (crystalline)

textureCrystallographic preferred orientationcrystallographic texture
Fiber texture is an example of the latter.
In materials science, texture is the distribution of crystallographic orientations of a polycrystalline sample (it is also part of the geological fabric).

Grain boundary

grain boundaries grain boundariescrystallite discontinuities
The areas where crystallites meet are known as grain boundaries.
A grain boundary is the interface between two grains, or crystallites, in a polycrystalline material.

Crystal

crystallinecrystalscrystalline solid
A crystallite is a small or even microscopic crystal which forms, for example, during the cooling of many materials. While the structure of a (monocrystalline) crystal is highly ordered and its lattice is continuous and unbroken, amorphous materials, such as glass and many polymers, are non-crystalline and do not display any structures, as their constituents are not arranged in an ordered manner.
Most inorganic solids are not crystals but polycrystals, i.e. many microscopic crystals fused together into a single solid.

Single crystal

single-crystalsingle crystalsmonocrystalline
While the structure of a (monocrystalline) crystal is highly ordered and its lattice is continuous and unbroken, amorphous materials, such as glass and many polymers, are non-crystalline and do not display any structures, as their constituents are not arranged in an ordered manner. Solid objects 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, single crystals of a nickel-based superalloy for turbojet engines, and some ice crystals which can exceed 0.5 meters in diameter).
In between the two extremes exist polycrystalline, which is made up of a number of smaller crystals known as crystallites, and paracrystalline phases.

Ceramic

ceramicsceramic materialsceramicist
Most inorganic solids are polycrystalline, including all common metals, many ceramics, rocks, and ice.
His model showed that microscopic pores in ceramic, mainly trapped at the junctions of microcrystalline grains, caused light to scatter and prevented true transparency.

Mosaicity

mosaic crystalrocking curveDarwin-Hamilton equations
When the crystallites are mostly ordered with just some random spread of orientations, one has a mosaic crystal.
A mosaic crystal is an idealized model of an imperfect crystal, imagined to consist of numerous small perfect crystals (crystallites) that are to some extent randomly misoriented.

Crystallinity

crystallineholocrystallinesemicrystalline
The extent to which a solid is crystalline (crystallinity) has important effects on its physical properties.
For instance, most metallic alloys are crystalline, but they usually comprise many independent crystalline regions (grains or crystallites) in various orientations separated by grain boundaries; furthermore, they contain other crystallographic defects (notably dislocations) that reduce the degree of structural perfection.

Scherrer equation

ScherrerShape factor (X-ray diffraction)x-ray diffraction
Thus, the (powder) "grain size" found by laser granulometry can be different from the "grain size" (rather, crystallite size) found by X-ray diffraction (e.g. Scherrer method), by optical microscopy under polarised light, or by scanning electron microscopy (backscattered electrons).
The Scherrer equation, in X-ray diffraction and crystallography, is a formula that relates the size of sub-micrometre crystallites, in a solid to the broadening of a peak in a diffraction pattern.

Monocrystalline silicon

monocrystallinemono-Sisilicon
Solid objects 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, single crystals of a nickel-based superalloy for turbojet engines, and some ice crystals which can exceed 0.5 meters in diameter).
Monocrystalline silicon differs from other allotropic forms, such as non-crystalline amorphous silicon—used in thin-film solar cells—and polycrystalline silicon, which consists of small crystals known as crystallites.

Metal

metalsmetal ionsmetal ion
Most inorganic solids are polycrystalline, including all common metals, many ceramics, rocks, and ice.
The metal workers involved heated gold with grains of the platinum alloy until the gold melted at which point the platinum group metals became bound within the gold.

Isotropy

isotropicisotropicallyanisotropic
If the individual crystallites are oriented completely at random, a large enough volume of polycrystalline material will be approximately isotropic.
This can be verified simply by investigating, e.g., a polycrystalline material under a polarizing microscope having the polarizers crossed: If the crystallites are larger than the resolution limit, they will be visible.

Paracrystalline

paracrystalsParacrystal model and theory
Polycrystalline structures and paracrystalline phases are in-between these two extremes.

Corrosion

corrosion resistancecorrodecorrosive
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.
Because of the elevated temperatures of welding and heat treatment, chromium carbides can form in the grain boundaries of stainless alloys.

Grain boundary strengthening

grain refinementHall-Petch relationshipHall–Petch
This crystallite size-strength relationship is given by the Hall–Petch relationship.
Grain-boundary strengthening (or Hall–Petch strengthening) is a method of strengthening materials by changing their average crystallite (grain) size.

Abnormal grain growth

discontinuous grain growthExaggerated grain growth
Abnormal or discontinuous grain growth, also referred to as exaggerated or secondary recrystallisation grain growth, is a grain growth phenomenon through which certain energetically favorable grains (crystallites) grow rapidly in a matrix of finer grains resulting in a bimodal grain size distribution.

Polycrystalline silicon

polysiliconmulti-crystalline siliconpolycrystalline
Polycrystalline silicon, also called polysilicon or poly-Si, is a high purity, polycrystalline form of silicon, used as a raw material by the solar photovoltaic and electronics industry.

Intergranular fracture

inter-granular crackingintergranular
Material fractures can be either intergranular or a transgranular fracture.

Magnetic domain

magnetic domainsdomaindomains
Grain boundaries are also present in magnetic domains in magnetic materials.
However most magnetic materials are polycrystalline, composed of microscopic crystalline grains.

Creep (deformation)

creepcreep resistancecreep strength
Grain boundary migration plays an important role in many of the mechanisms of creep.
The coil geometry and supports are therefore designed to limit the stresses caused by the weight of the filament, and a special tungsten alloy with small amounts of oxygen trapped in the crystallite grain boundaries is used to slow the rate of Coble creep.

Superalloy

superalloysadvanced metal alloyssuper alloy
Because of the dangers of grain boundaries in certain materials such as superalloy turbine blades, great technological leaps were made to minimize as much as possible the effect of grain boundaries in the blades.
Single-crystal superalloys (SX or SC superalloys) are formed as a single crystal using a modified version of the directional solidification technique, so there are no grain boundaries in the material.

Directional solidification

directionally solidifieddirectionally solidifies
The result was directional solidification processing in which grain boundaries were eliminated by producing columnar grain structures aligned parallel to the axis of the blade, since this is usually the direction of maximum tensile stress felt by a blade during its rotation in an airplane.
Directional solidification (in zone melting) is frequently employed as a purification step in the production of multicrystalline silicon for solar cells.

Crystallography

crystallographercrystallographiccrystallographically

Sulfur

sulphurSbrimstone
Sulfur, while usually polycrystalline, may also occur in other allotropic forms with completely different properties.

Allotropy

allotropeallotropesallotropic
Sulfur, while usually polycrystalline, may also occur in other allotropic forms with completely different properties.

Powder

powderspowderedpowdery
Although crystallites are referred to as grains, powder grains are different, as they can be composed of smaller polycrystalline grains themselves.