Dislocations are what type of defects?

• A. Planar defects
• B. Linear defects
• C. Point defects
• D. Volume defects

Answer: (B)

Dislocations are linear defects, meaning they are disruptions that extend along a line through the crystal. They are one-dimensional imperfections in the lattice, unlike point defects (vacancies, interstitials) which are confined to a single site, planar defects (grain boundaries, stacking faults) which are two-dimensional, or volume defects (voids, precipitates) which occupy a three-dimensional region. Dislocations come in common forms like edge and screw dislocations and are described by the Burgers vector; their motion enables easy plastic deformation by slip along close-packed planes, so they matter a lot for how a material yields and hardens.