ME 2733 Chapter : Dislocations
Document Summary
Dislocations important points: dislocations are linear defects, i. e. , defects within crystalline materials appearing as lines. These are not necessarily straight and most often curved and non-linear in nature: defects occur at the atomic level, and, so, can be viewed only with high resolution electron microscope. In viewed sections the dislocations appear as curvy lines: these are produced by atomic planes that have the highest density of atoms, i. e. , by close packed planes or those that have highest packing density. {111} family of planes in fcc, {110} family of planes in bcc and {001} family of planes in hcp crystals. In fcc and hcp the close packed planes are involved. In bcc crystals, the {110} sets of planes have the maximum packing density: there are two basic types of dislocations: edge and screw types. The others are combinations of two or more of the same kind or of mixed edge and screw types.
