Refers to crystalline materials that are composed of more than one crystal or grain. Sometimes the terms amorphous, glassy, and vitreous are used synonymously. The solid state wherein there is no long-range atomic order. The combination of unit cell edge lengths and interaxial angles that defines the unit cell geometry.Ī set of three integers (four for hexagonal) that designate crystallographic planes, as determined from reciprocals of fractional axial intercepts. The regular geometrical arrangement of points in crystal space.
Having identical values of a property in all crystallographic directions. The HCP unit cell is of hexagonal geometry and is generated by the stacking of close-packed planes of atoms. The interface separating two adjoining grains having different crystallographic orientations.Ī crystal structure found for some metals. Within the cubic unit cell, atoms are located at all corner and face-centered positions.Īn individual crystal in a polycrystalline metal or ceramic. There are seven different crystal systems.Ĭonstructive interference of x-ray beams that are scattered by atoms of a crystal.Ī crystal structure found in some of the common elemental metals. This geometry is specified in terms of the relationships between edge lengths and interaxial angles.
It is defined in terms of the unit cell geometry and the atom positions within the unit cell.Ī scheme by which crystal structures are classified according to unit cell geometry. The state of a solid material characterized by a periodic and repeating three-dimensional array of atoms, ions, or molecules.įor crystalline materials, the manner in which atoms or ions are arranged in space. The number of atomic or ionic nearest neighbors.
Within the cubic unit cell, atoms are located at corner and cell center positions.Ī relationship that stipulates the condition for diffraction by a set of crystallographic planes. The fraction of the volume of a unit cell that is occupied by 'hard sphere' atoms or ions.Ī common crystal structure found in some elemental metals. The possibility of the existence of two or more different crystal structures for a substance (generally an elemental solid).Įxhibiting different values of a property in different crystallographic directions. The height of the unit cell, which more challenging to calculate, is c = 4r(2/3)1/2. Atoms on adjacent corners of the base are in contact, thus a = b = 2r. Because the atoms are in 'physical contact', these lengths are directly related to the atomic radius, r. 3ds max 2010 64 bit free download full version with crack version. It is dimensionless and always less than unity. Additional Engineering FlashcardsĪtomic packing factor (APF) or packing fraction is the fraction of volume in a crystal structure that is occupied by atoms. Click here to study/print these flashcards.Ĭreate your own flash cards! Sign up here.
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