TWINS AND COMPLEMENTARY TWINS IN SHOCK HARDENED IRON

By analysing the displacements produced in an existing ‘deformation band’ by its interaction with twin boundaries, it has been shown that a twin and a complementary twin having identical composition planes may form within the same grain during shock deformation of iron. The deformation sequence must consist of compressive and tensile stresses because a reversal in shear stresses is required to form the twin-complementary twin pair. Twins are observed to fragment along the traces of certain crystallographic planes; the origin of these traces has been explained. The observations regarding the fragmenting twins are consistent with the idea that dislocations in the crystal ahead of the advancing boundary may constitute the primary barrier to its motion. © 1969 Taylor & Francis Group, LLC.