190 Point Defects GJ >An interstitial is an atom occupying an interstitial site,normally not occupied in the structure of a "perfect"lattice. >A self interstitial is an atom from the crystal that is crowded into an interstitial site. >Interstitial sites may be also occupied by chemical impurities(different atoms)
Point Defects An interstitial is an atom occupying an interstitial site, normally not occupied in the structure of a “perfect” lattice. A self interstitial is an atom from the crystal that is crowded into an interstitial site. Interstitial sites may be also occupied by chemical impurities (different atoms)
190 Point defects Because the atoms exist as charged ions, when defects structures are considered, conditions of electroneutrality must be maintained. Frenkel defect: Schottky defect: Formed by a cation leaving its A cation vacancy-anion normal position and moving vacancy pair. into an interstitial site
Point defects Because the atoms exist as charged ions, when defects structures are considered, conditions of electroneutrality must be maintained. Frenkel defect: Formed by a cation leaving its normal position and moving into an interstitial site. Schottky defect: A cation vacancy-anion vacancy pair
190 3.1.3 LINEAR DEFECTS: NGJ DISLOCATIONS Two main types:edge dislocation or screw dislocation:essential for the plastic deformation of materials In a commercial metal(i.e.Cu)there are approximate 108 dislocation per cm3
3.1.3 LINEAR DEFECTS: DISLOCATIONS • Two main types: edge dislocation or screw dislocation: essential for the plastic deformation of materials • In a commercial metal(i. e. Cu) there are approximate 108 dislocation per cm3
190 LINEAR DEFECTS:DISLOCATIONS (1)EDGE DISLOCATION: An extra portion of atoms,or half-plane, the edge of which terminates within the crystal. Bu吧ers vector It is a linear defect that compressive centers around the line Edge dislcation that is defined along the line end of the extra half- tensile plane of atoms
LINEAR DEFECTS: DISLOCATIONS (1)EDGE DISLOCATION: An extra portion of atoms, or half-plane, the edge of which terminates within the crystal. It is a linear defect that centers around the line that is defined along the end of the extra halfplane of atoms
190>习 悠© IONGJI UN1VER、个令 EDGE DISLOCATION:MOVEMENT
EDGE DISLOCATION: MOVEMENT