The possible cross-slip planes are determined by the crystal system. In body centered cubic (BCC) metals, a screw dislocation with b=0.5<11> can glide on {110} planes or {211} planes. In face centered cubic (FCC) metals, screw dislocations can cross-slip from one {111} type plane to another. However, in FCC metals, pure screw dislocations dissociate into two mixed partial dislocations on a {111} plane, and the extended screw dislocation can only glide on the plane containing the two partial dislocations. The Friedel-Escaig mechanism and the Fleischer mechanism have been proposed to explain the cross-slip of partial dislocations in FCC metals.
