CBE30361 Lecture Notes - Lecture 9: Burgers Vector
9 Feb 2016
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Atoms missing or in irregular places in the lattice (vacancies, interstitials, impurities) Groups of atoms in irregular positions (e. g. screw and edge dislocations) The interfaces between homogeneous regions of the material (grain boundaries, external surfaces) Appear due to the vibrational motion of the atoms/molecules. Calculate the number of vacancies in cu (1cm3) at 27*c. Qv = . 9 ev/atom, p = 8. 4 g/cm3, acu = 63. 5 g/mol. Solid solution of b in a (i. e. , random distribution of point defects) substitutional solid solution. Solute atoms take the place of some of the solvent atoms. Solute atoms are much smaller than the solvent atoms. Solute atoms fit in the spaces between the solvent atoms. Solid solution of b in a plus particles of a new phase. Generally more solute goes into solution when it has higher valency than solvent. Atomic size (cid:1870)(cid:3030)(cid:3048) = 0. 128 (cid:1866)(cid:1865),(cid:1853)(cid:1866)(cid:1856) (cid:1870)(cid:3015)(cid:3036) = 0. 125 (cid:1866)(cid:1865). (cid:1844)% = 2. 3%
