Stacking-fault tetrahedra in deformed face-centred cubic metals

Abstract
Stacking-fault tetrahedra have been observed in plastically deformed specimens of copper, silver, gold and several alloys. A dislocation reaction is proposed for the formation of these defects during deformation. From the size of the largest tetrahedra, estimates of stacking-fault energy are made which indicate that the stacking-fault energy of silver is less than that of gold and copper.