Term
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Definition
| The special name given to the close-packed plane in hexagonal close-packed unit cells. |
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Term
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Definition
| A group of atoms associated with a lattice point (same as motif). |
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Term
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Definition
| A process used to form plastic bottles. |
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Term
| Bose-Einstein condensate (BEC) |
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Definition
| A newly experimentally verified state of a matter in which a group of atoms occupy the same guantum ground state. |
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Term
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Definition
| The relationship describing the angle at which a beam of x-rays of a particular wavelength diffract from crystallographic planes of a given interplanar spacing. |
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Term
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Definition
| The fourteen possible lattices that can be created using lattice points. |
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Term
| Chemical vapor deposition (CVD) |
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Definition
| A process used for production of inorganic thin films or powders involving decomposition of precursors followed by chemical reaction in the vapor phase. |
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Term
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Definition
| Directions in a crystal along which atoms are in contact. |
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Term
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Definition
| Structures showing a packing fracture of 0.74 (FCC and HCP). |
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Term
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Definition
| The number of nearest neighbors to an atom in its atomic arrangement. |
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Term
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Definition
| The arrangement of atoms in a material into a regular repeatable lattice. |
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Term
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Definition
| Cubic, tetragonal, orthorhombic, hexogonal, monoclinic, rhombohedral, and triclinic arrangements of points in space that lead to 14 Bravais lattices and hundreds of crystal structures. |
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Term
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Definition
| Materials comprised of one or many small crystals or grains. |
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Term
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Definition
| The process responsible for the formation of crystals, typically in an amorphous material. |
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Term
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Definition
| An interstitial position that has a coordination number of eight. An atom or ion in the cubic site touches eight other atoms or ions. |
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Term
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Definition
| A microstructural feature representing a disruption in the perfect periodic arrangement of atom in a crystalline material. This term is not used to convey the presence of a flaw in the material. |
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Term
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Definition
| Mass per unit volume of a material, usually in units of g/m^3. |
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Term
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Definition
| A special type of face-centered cubic crystal structure found in carbon, silicon, and other covalently bonded materials. |
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Term
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Definition
| The constructive or reinforcement of a beam of x-rays or electrons interacting with a material. The diffracted beam provides useful information concerning the structure of the material. |
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Term
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Definition
| Crytallographic directions that all have the same characteristics, although their "sense" is different. Denoted by <> brackets. |
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Term
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Definition
| A method used to determine the level of crystallinity at relatively smaller length scales. Based on the diffraction of electrons typically involving use of a transmission electron microscope. |
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Term
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Definition
| A process to manufacture large pieces of flat glass in which molten glass is floated on a bath of tin. |
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Term
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Definition
| A family of materials typically derived from molten inorganic glasses an processed into crystalline materials with very fine grain size and improved mechanical properties. |
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Term
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Definition
| Solid, non-crystalline materials (typically derived from the molten state) that have only short-range atomic order. |
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Term
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Definition
| A small crystal in a polycrystalline material. |
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Term
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Definition
| Regions between grains of a polycrystalline material. |
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Term
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Definition
| Distance between two adjacent parallel planes with the same Miller indices. |
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Term
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Definition
| Locations between the "normal" atoms or ions in a crystal into which another--usually different--atom or ion is placed. Typically, the size of this interstitial location is smaller than the atom or ion that is to be introduced. |
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Term
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Definition
| Having the same properties in all directions. |
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Term
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Definition
| A collection of points that divide space into smaller equally sized segments. |
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Term
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Definition
| The lengths of the sides of the unit cell and the angles between those sides. The lattice parameters describe the size and shape of the unit cell. |
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Term
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Definition
| Points that make up the lattice. The surroundings of each lattice point are identical anywhere in the material. |
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Term
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Definition
| The number of lattice points per unit length along a direction. |
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Term
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Definition
| Polymeric materials that are typically amorphous but can become partially crystalline when an external electric field is applied. The effect of the electric field is reversible. Such materials are used in liquid crystal displays. |
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Term
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Definition
| A regular repetitive arrangement of atoms in a solid which extends over a very large distance. |
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Term
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Definition
| Amorphous metals or alloys obtained using rapid solidification. |
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Term
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Definition
| A special shorthand notation to describe the crystallographic planes in hexagonal close-packed unit cells. |
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Term
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Definition
| A shorthand notation to describe certain crystallographic directions and planes in a material. Denoted by [] brackets. A negative number is represented by a bar over the number. |
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Term
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Definition
| A group of atoms affiliated with a lattice point (same as a basis). |
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Term
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Definition
| An interstitial position that has a coordination number of six. An atom or ion in the octahedral site touches six other atoms or ions. |
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Term
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Definition
| The fraction of space in a unit cell occupied by atoms. |
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Term
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Definition
| The fraction of a direction (linear-packing fraction) or a plane (planar-packing factor) that is actually covered by atoms or ions. When one atom is located at each lattice point, the linear packing fraction along a direction is the product of the linear density and twice the atomic radius. |
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Term
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Definition
| The number of atoms per unit area whose centers lie on the plane. |
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Term
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Definition
| Crystallographic planes that all have the same characteristics, although their orientations are different. Denoted by {} braces. |
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Term
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Definition
| A material comprised of many grains. |
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Term
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Definition
| Compounds exhibiting more than one type of crystal structure. |
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Term
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Definition
| A technique used to cool metals and alloys very quickly. |
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Term
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Definition
| The distance from one lattice point to the adjacent lattice point along a direction. |
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Term
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Definition
| The regular and predictable arrangement of the atoms over a short distance--usually one or two atom spacings. |
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Term
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Definition
| The sequence in which close-packed planes are stacked. If the sequence is ABABAB, a hexagonal close-packed unit cell is produced; if the sequence is ABCABCABC, a face-centered cubic structure is produced. |
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Term
| Stress-induced crystallization |
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Definition
| The process of forming crystals by the application of an external stress. Typically, a significant fraction of many amorphous plastics can be crystallized in this fashion, making them stronger. |
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Term
| Tranmission electron microscopy (TEM) |
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Definition
| A technique for imaging and analysis of microstructures using a high-energy electron beam. |
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Term
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Definition
| An interstitial position that has a coordination number of four. An atom or ion in the tetrahedral site touches four other atoms or ions. |
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Term
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Definition
| The structure produced when atoms are packed together with a four-fold coordination. |
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Term
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Definition
| A subdivision of the lattice that still retains the overall characteristics of the entire lattice. |
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Term
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Definition
| A technique for analysis of crystalline materials using a beam of x-rays. |
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Term
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Definition
| American Society for Testing and Materials |
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Term
| A S T M g r a i n s i z e n u m b e r ( n ) |
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Definition
| A m e a s u r e o f t h e s i z e o f t h e g r a i n s i n a c r y s t a l l i n e m a t e r i a l o b t a i n e d b y c o u n t i n g t h e n u m b e r o f g r a i n s p e r s q u a r e i n c h a t m a g n i f i c a t i o n x 1 0 0 . |
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Term
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Definition
| A h e a t t r e a t m e n t t h a t t y p i c a l l y i n v o l v e s h e a t i n g a m e t a l l i c m a t e r i a l t o a h i g h t e m p e r a t u r e f o r a n e x t e n d e d p e r i o d o f t i m e , c o n d u c t e d w i t h a v i e w t o l o w e r t h e d i s l o c a t i o n d e n s i t y a n d h e n c e i m p a r t d u c t i l i t y . |
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Term
| B u r g e r s v e c t o r |
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Definition
| T h e d i r e c t i o n a n d d i s t a n c e t h a t a d i s l o c a t i o n m o v e s i n e a c h s t e p , a l s o k n o w n a s s l i p v e c t o r . |
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Term
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Definition
| E l e m e n t s o r c o m p o u n d s t y p i c a l l y a d d e d , i n k n o w n c o n c e n t r a t i o n s a n d a p p e a r i n g a t s p e c i f i c p l a c e s w i t h i n t h e m i c r o s t r u c t u r e , t o e n h a n c e t h e p r o p e r t i e s o r p r o c e s s i n g o f a m a t e r i a l . |
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Term
| C r i t i c a l r e s o l v e d s h e a r s t r e s s |
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Definition
| T h e s h e a r s t r e s s r e q u i r e d t o c a u s e a d i s l o c a t i o n t o m o v e a n d c a u s e s l i p . |
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Term
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Definition
| A c h a n g e i n t h e s l i p s y s t e m o f a d i s l o c a t i o n . |
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Term
| D e f e c t c h e m i c a l r e a c t i o n s |
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Definition
| R e a c t i o n s u s i n g t h e K r ö g e r - V i n k n o t a t i o n t o d e s c r i b e d e f e c t c h e m i s t r y . T h e r e a c t i o n s m u s t b e w r i t t e n i n s u c h a w a y t h a t m a s s a n d e l e c t r i c a l c h a r g e s a r e b a l a n c e d a n d s t o i c h i o m e t r y o f s i t e s i s m a i n t a i n e d . T h e e x i s t e n c e o f d e f e c t s p r e d i c t e d b y s u c h a c t i o n s n e e d s t o b e v e r i f i e d e x p e r i m e n t a l l y . |
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Term
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Definition
| A l i n e i m p e r f e c t i o n i n a c r y s t a l l i n e m a t e r i a l . M o v e m e n t o f d i s l o c a t i o n s h e l p s e x p l a i n h o w m e t a l l i c m a t e r i a l s d e f o r m . I n t e r f e r e n c e w i t h t h e m o v e m e n t o f d i s l o c a t i o n s h e l p s e x p l a i n h o w m e t a l l i c m a t e r i a l s a r e s t r e n g t h e n e d . |
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Term
| D i s l o c a t i o n d e n s i t y |
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Definition
| T h e t o t a l l e n g t h o f d i s l o c a t i o n l i n e p e r c u b i c c e n t i m e t e r o f m a t e r i a l . |
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Term
| D i s p e r s i o n s t r e n g t h e n i n g |
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Definition
| A m e c h a n i s m b y w h i c h g r a i n s o f a n a d d i t i o n a l c o m p o u n d o r p h a s e a r e i n t r o d u c e d i n t h e g r a i n s o f a p o l y c r y s t a l l i n e m e t a l l i c m a t e r i a l . T h e s e s e c o n d p h a s e c r y s t a l s s e r v e a s s t o p s i g n s f o r d i s l o c a t i o n s t h e r e b y c a u s i n g a n i n c r e a s e i n t h e s t r e n g t h o f a m e t a l l i c m a t e r i a l . |
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Term
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Definition
| A s m a l l r e g i o n o f a f e r r o e l e c t r i c , f e r r o m a g n e t i c o r f e r r i m a g n e t i c m a t e r i a l s i n w h i c h t h e d i r e c t i o n o f d i e l e c t r i c p o l a r i z a t i o n ( f o r f e r r o e l e c t r i c ) o r m a g n e t i z a t i o n ( f o r f e r r o m a g n e t i c o r f e r r o m a g n e t i c ) r e m a i n s t h e s a m e . |
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Term
| D o m a i n b o u n d a r i e s |
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Definition
| R e g i o n b e t w e e n d o m a i n s i n a m a t e r i a l . |
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Term
| E d g e d i s l o c a t i o n s |
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Definition
| A d i s l o c a t i o n i n t r o d u c e d i n t o t h e c r y s t a l b y a d d i n g a n e x t r a h a l f p l a n e o f a t o m s . |
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Term
| E l a s t i c d e f o r m a t i o n |
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Definition
| D e f o r m a t i o n t h a t i s f u l l y r e c o v e r e d w h e n t h e s t r e s s t h a t i s c a u s i n g i t i s r e m o v e d |
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Term
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Definition
| T i n y h o l e s c r e a t e d a t a r e a s w h e r e d i s l o c a t i o n s m e e t t h e s u r f a c e . T h e s e a r e u s e d t o e x a m i n e t h e p r e s e n c e a n d n u m b e r d e n s i t y o f d i s l o c a t i o n s . |
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Term
| E x t e n d e d d e f e c t s |
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Definition
| D e f e c t s t h a t i n v o l v e s e v e r a l a t o m s / i o n s a n d t h u s o c c u r o v e r a f i n i t e v o l u m e o f t h e c r y s t a l l i n e m a t e r i a l ( e . g . , d i s l o c a t i o n s , s t a c k i n g f a u l t s , e t c . ) . |
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Term
| E x t r i n s i c s e m i c o n d u c t o r |
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Definition
| S e m i c o n d u c t o r s c o n t a i n i n g d o p a n t s o r i m p u r i t i e s . |
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Term
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Definition
A material that also develops a spontaneous and reversible magnetization (e.g., Fe3O4). It is different from a ferromagnetic material in that the magnetic moments of different ions are not all in the same direction. |
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Term
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Definition
A dielectric material that develops a spontaneous and reversible electric polarization (e.g., PZT, BaTiO3). |
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Term
| F e r r o m a g n e t i c |
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Definition
| A m a t e r i a l t h a t d e v e l o p s a s p o n t a n e o u s a n d r e v e r s i b l e m a g n e t i z a t i o n . |
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Term
| F r e n k e l d e f e c t |
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Definition
| A p a i r o f p o i n t d e f e c t s p r o d u c e d w h e n a n i o n m o v e s t o c r e a t e a n i n t e r s t i t i a l s i t e , l e a v i n g b e h i n d a v a c a n c y . |
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Term
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Definition
| O n e o f t h e c r y s t a l s p r e s e n t i n a p o l y c r y s t a l l i n e m a t e r i a l . |
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Term
| G r a i n b o u n d a r y |
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Definition
| A s u r f a c e d e f e c t r e p r e s e n t i n g t h e b o u n d a r y b e t w e e n t w o g r a i n s . T h e c r y s t a l h a s a d i f f e r e n t o r i e n t a t i o n o n e i t h e r s i d e o f t h e g r a i n b o u n d a r y . |
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Term
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Definition
The relationship between yield strength and grain size in a metallic material--that is, σy = σ0 + Kd-1/2. |
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Term
| I m a g e a n a l y s i s |
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Definition
| A t e c h n i q u e t h a t i s u s e d t o a n a l y z e i m a g e s o f m i c r o s t r u c t u r e s t o o b t a i n q u a n t i t a t i v e i n f o r m a t i o n o n g r a i n s i z e , s h a p e , g r a i n s i z e d i s t r i b u t i o n , e t c . |
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Term
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Definition
| E l e m e n t s o r c o m p o u n d s t h a t f i n d t h e i r w a y i n t o a m a t e r i a l , o f t e n o r i g i n a t i n g f r o m p r o c e s s i n g o r r a w m a t e r i a l s a n d t y p i c a l l y h a v e a d e l e t e r i o u s e f f e c t o n t h e p r o p e r t i e s o r p r o c e s s i n g o f a m a t e r i a l . |
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Term
| I n t e r s t i t i a l d e f e c t |
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Definition
| A p o i n t d e f e c t p r o d u c e d w h e n a n a t o m i s p l a c e d i n t o t h e c r y s t a l a t a s i t e t h a t i s n o r m a l l y n o t a l a t t i c e p o i n t . |
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Term
| I n t e r s t i t i a l c y |
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Definition
| A p o i n t d e f e c t c a u s e d w h e n a n o r m a l a t o m o c c u p i e s a n i n t e r s t i t i a l s i t e i n t h e c r y s t a l . |
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Term
| I n t r i n s i c s e m i c o n d u c t o r |
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Definition
| A s e m i c o n d u c t o r t h a t c o n t a i n s n o d o p a n t s o r i m p u r i t i e s . |
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Term
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Definition
| Defects such as dislocations in which atoms or ions are missing in a row. |
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Term
| M e t a l l o g r a p h y |
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Definition
| P r e p a r a t i o n o f a m e t a l l i c s a m p l e o f a m a t e r i a l b y p o l i s h i n g a n d e t c h i n g s o t h a t t h e s t r u c t u r e c a n b e d e t e r m i n e d u s i n g a m i c r o s c o p e . |
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Term
| M i x e d d i s l o c a t i o n |
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Definition
| A d i s l o c a t i o n t h a t c o n t a i n s p a r t l y e d g e c o m p o n e n t s a n d p a r t l y s c r e w c o m p o n e n t s . |
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Term
| n - t y p e s e m i c o n d u c t o r |
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Definition
| A s e m i c o n d u c t o r t h a t i s d o p e d w i t h e l e m e n t s t h a t d o n a t e e l e c t r o n s ( e . g . , P - d o p e d S i ) . |
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Term
| p - t y p e s e m i c o n d u c t o r |
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Definition
| A s e m i c o n d u c t o r t h a t i s d o p e d w i t h e l e m e n t s t h a t a c c e p t e l e c t r o n s ( e . g . , B - d o p e d S i ) . |
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Term
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Definition
The shear stress, whichdepends on the Burgers vector and the interplanar spacing, required to cause a dislocation to move--that is, τ = c exp(-kd/b). |
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Term
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Definition
| I m p e r f e c t i o n s , s u c h a s v a c a n c i e s , t h a t a r e l o c a t e d t y p i c a l l y a t o n e ( i n s o m e c a s e s a f e w ) s i t e s i n t h e c r y s t a l . |
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Term
| P r e c i p i t a t i o n s t r e n g t h e n i n g |
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Definition
| S t r e n g t h e n i n g o f m e t a l s a n d a l l o y s b y f o r m a t i o n o f t i n y p r e c i p i t a t e s i n s i d e t h e g r a i n s . T h e s m a l l p r e c i p i t a t e s h e l p r e s i s t d i s l o c a t i o n m o t i o n . |
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Term
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Definition
The relationshop between shear stress, the applied stress, and the orientation of the slip system--that is, τ = σ cos λ cos φ. |
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Term
| S c h o t t k y d e f e c t |
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Definition
| A p o i n t d e f e c t i n i o n i c a l l y b o n d e d m a t e r i a l s . I n o r d e r t o m a i n t a i n a n e u t r a l c h a r g e , a s t o i c h i o m e t r i c n u m b e r o f c a t i o n a n d a n i o n v a c a n c i e s m u s t f o r m . |
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Term
| S c r e w d i s l o c a t i o n |
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Definition
| A d i s l o c a t i o n p r o d u c e d b y s k e w i n g a c r y s t a l s o t h a t o n e a t o m i c p l a n e p r o d u c e s a s p i r a l r a m p a b o u t t h e d i s l o c a t i o n . |
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Term
| S e c o n d - p h a s e s t r e n g t h e n i n g |
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Definition
| A m e c h a n i s m b y w h i c h g r a i n s o f a n a d d i t i o n a l c o m p o u n d o r p h a s e a r e i n t r o d u c e d i n t h e g r a i n s o f a p o l y c r y s t a l l i n e m a t e r i a l . T h e s e s e c o n d p h a s e c r y s t a l s s e r v e a s s t o p s i g n s f o r d i s l o c a t i o n s t h e r e b y c a u s i n g a n i n c r e a s e i n t h e s t r e n g t h o f a m e t a l l i c m a t e r i a l . |
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Term
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Definition
| A p r o c e s s f o r f o r m i n g a d e n s e m a s s b y h e a t i n g c o m p a c t e d p o w d e r s . |
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Term
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Definition
| D e f o r m a t i o n o f a m e t a l l i c m a t e r i a l b y t h e m o v e m e n t o f d i s l o c a t i o n s t h r o u g h t h e c r y s t a l . |
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Term
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Definition
| C o l l e c t i o n o f m a n y s l i p l i n e s , o f t e n e a s i l y v i s i b l e . |
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Term
| S l i p d i r e c t i o n |
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Definition
| T h e d i r e c t i o n i n t h e c r y s t a l i n w h i c h t h e d i s l o c a t i o n m o v e s . T h e s l i p d i r e c t i o n i s t h e s a m e a s t h e d i r e c t i o n o f t h e B u r g e r s v e c t o r . |
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Term
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Definition
| A v i s i b l e l i n e p r o d u c e d a t t h e s u r f a c e o f a m e t a l l i c m a t e r i a l b y t h e p r e s e n c e o f s e v e r a l t h o u s a n d d i s l o c a t i o n s . |
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Term
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Definition
| T h e p l a n e s w e p t o u t b y t h e d i s l o c a t i o n l i n e d u r i n g s l i p . N o r m a l l y t h e s l i p p l a n e i s a c l o s e - p a c k e d p l a n e , i f o n e e x i s t s i n t h e c r y s t a l s t r u c t u r e . |
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Term
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Definition
| T h e c o m b i n a t i o n o f t h e s l i p p l a n e a n d t h e s l i p d i r e c t i o n . |
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Term
| S m a l l a n g l e g r a i n b o u n d a r y |
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Definition
| A n a r r a y o f d i s l o c a t i o n s c a u s i n g a s m a l l m i s o r i e n t a t i o n o f t h e c r y s t a l a c r o s s t h e s u r f a c e o f t h e i m p e r f e c t i o n . |
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Term
| S t a c k i n g f a u l t |
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Definition
| A s u r f a c e d e f e c t i n F C C m e t a l s c a u s e d b y t h e i m p r o p e r s t a c k i n g s e q u e n c e o f c l o s e - p a c k e d p l a n e s . |
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Term
| S u b s t i t u t i o n a l d e f e c t |
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Definition
| A p o i n t d e f e c t p r o d u c e d w h e n a n a t o m i s r e m o v e d f r o m a r e g u l a r l a t t i c e p o i n t a n d r e p l a c e d w i t h a d i f f e r e n t a t o m , u s u a l l y o f a d i f f e r e n t s i z e . |
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Term
| S u r f a c e d e f e c t s |
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Definition
| I m p e r f e c t i o n s , s u c h a s g r a i n b o u n d a r i e s , t h a t f o r m a t w o - d i m e n s i o n a l p l a n e w i t h i n t h e c r y s t a l . |
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Term
| T h e r m a l g r o o v i n g |
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Definition
| A t e c h n i q u e u s e d f o r o b s e r v i n g m i c r o s t r u c t u r e s i n c e r a m i c m a t e r i a l s , i n v o l v e s h e a t i n g , f o r a s h o r t t i m e , a p o l i s h e d s a m p l e t o a t e m p e r a t u r e s l i g h t l y b e l o w t h e s i n t e r i n g t e m p e r a t u r e . |
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Term
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Definition
| A s m a l l a n g l e g r a i n b o u n d a r y c o m p o s e d o f a n a r r a y o f e d g e d i s l o c a t i o n s . |
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Term
| T r a n s m i s s i o n e l e c t r o n m i c r o s c o p e ( T E M ) |
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Definition
| A n i n s t r u m e n t t h a t , b y p a s s i n g a n e l e c t r o n b e a m t h r o u g h a m a t e r i a l , c a n d e t e c t m i c r o s c o p i c s t r u c t u r a l f e a t u r e s . |
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Term
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Definition
| A s u r f a c e d e f e c t a c r o s s w h i c h t h e r e i s a m i r r o r i m a g e m i s o r i e n t a t i o n o f t h e c r y s t a l s t r u c t u r e . T w i n b o u n d a r i e s c a n a l s o m o v e a n d c a u s e d e f o r m a t i o n o f t h e m a t e r i a l . |
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Term
| T w i s t b o u n d a r y |
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Definition
| A s m a l l a n g l e g r a i n b o u n d a r y c o m p o s e d o f a n a r r a y o f s c r e w d i s l o c a t i o n s . |
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Term
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Definition
| A n a t o m o r a n i o n m i s s i n g f r o m i t s r e g u l a r c r y s t a l l o g r a p h i c s i t e . |
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Term
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Definition
| The characteristic of an element being able to exist in more than one crystal structure, depending on temperature and pressure. |
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Term
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Definition
| Materials, including glasses, that have no long-range order, or crystal structure. |
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Term
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Definition
| Having different properties in different directions. |
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Term
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Definition
| Defects such as vacancies, dislocations etc. occurring over a length-scale comparable to few interatomic distances. |
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Term
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Definition
| The apparent radius of an atom, typically calculated from the dimensions of the unit cell, using close-packed directions (depends upon coordination number). |
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Term
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Definition
| The fraction of space in a unit cell occupied by atoms. |
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Term
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Definition
| A conjecture made by Johannes Kepler in 1611 that stated that the maximum packing fraction with spheres of uniform size could not exceed π/√18. In 1998 Thomas Hales proved this to be true. |
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Term
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Definition
| A system used to indicate point defects in materials. The main body of the notation indicates the type of defect or the element involved. The subscript indicates the location of the point defect and the superscript indicates the effective positive (.) or negative (')charge. |
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Term
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Definition
| Askeland, Donald and Pradeep Phulé. The Science and Engineering of Materials, 4E. ISBN 0-534-95373-5. |
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