This page contains materials for the session on point and line defects in crystals. It features a 1hour lecture video, and also presents the prerequisites, learning objectives, reading assignment, lecture slides, homework with solutions, and resources for further study. The general theoretical concepts and various experimental observations connected with the formation and mobility of vacancies and their complexes, their effect on the physical properties of metals, are described. A point defect is any defect that involves only a single particle a lattice point or sometimes a very small set of points. The formation of secondary defects by vacancy condensation, the interaction. A self interstitial atom is an extra atom that has crowded its way into an interstitial void in the crystal structure. By engineering defects, metals with bespoke performance might be. Electric and thermal conductivity in metals strongly reduced by point defects. The size of the defect could be one atom, or two atomic diameters, which is just like a point. This term is positive for vacancies and negative for interstitials.
Point defects are where an atom is missing or is in an irregular place in the lattice structure. The influence of point defects on the kinetics of plastic deformation is highly diversified. A point defect is a very localised disruption in the regularity of a lattice. Mechanical properties of metals are most sensitive to the presence of point defects. Electronic conductivity in semiconductors controlled by substitution defects. Lu discuss a strategy, alternative to alloying, to tailor the mechanical properties of metals. Point defects include self interstitial atoms, interstitial impurity atoms, substitutional atoms and vacancies.