Interaction of Dislocations and Point Defects

The partial dislocations described in copper and similar materials are not the only ones that can be described, and a number of other types are well known, including Frank partial dislocations, which mediate in a different slip process. 

Dislocation density is measured as the total length of dislocation lines in a unit volume of crystal, meters per meter cubed. However, experimentally it is often simpler to determine the number of dislocations that intersect a surface, so that a common measure of dislocation density is the number of dislocation lines threading a surface, that is, the number per meter squared. In a fairly typical material there will be on the order of 108 dislocation lines crossing every square centimeter of solid. However, it is known that if a solid is deformed, the dislocation density rises, perhaps by a factor of 103 or 104. Clearly, dislocations must be able to multiply under the conditions that lead to deformation. 

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INTERACTION OF DISLOCATIONS AND POINT DEFECTS 3.7.1 Dislocation Loops... 

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