Formation of faulted defects in copper by moving boundaries

Abstract

Direct observations, using electron microscopy, are presented on the formation of faulted defects left behind moving high‐angle grain boundaries in thin foils of copper at room temperature. Dislocation mechanisms are proposed for the formation of these defects at, and their detachment from a moving boundary.

The formation of grain boundary gamma during cooling of Ti46Al8Nb

“…It may well be that this is a common product at such cooling rates and that observation at the optical and SEM level has led to the view that they are fine alpha/gamma lamellae. The formation of such structures is perhaps analogous to the generation of twins or faults behind high angle grain boundaries during recrystallisation [14] where it is suggested that partial dislocations in grain boundaries generate such structures as they move as part of the boundary. Thus relatively rapid growth of the gamma away from the original boundary could leave behind it either twinned regions or high defect densities or both depending upon the defect density in the boundary and on the nature of these defects and on the velocity of the boundary.…”