Chapter Imperfections in Crystals Lesson seventeen
§5.1 ntroduction 1. Classification Ideal or perfect crystal real or defect crystal According to dimension point defect: vacancies, interstitial atoms line defect: dislocation planar defect: stacking fault o volume defect: mosaic structure
2. Effects physical properties(point defect) mechanical properties(dislocation) metallurgical properties(all of the defects)
§5.2 Point defects I Classification: 1. Schottky defect 2. Frenkel defect only vacancies pairs of vacancy and interstitial atom Schottky defect Frenkel defect
only vacancies pairs of vacancy and interstitial atom
Equi libr ium concentration of point defects Equilibrium concentration of point defects in metal △G,=△H1-7(△S,+△Sm) Suppose we introduce n vacancies into a crystal containing N atom sites Determine: C N
( ) v v v m G H T S S N n Cv