Dislocation density of pure copper processed by accumulative roll bonding and equal-channel angular pressing

The dislocation density of pure copper fabricated by two severe plastic deformation (SPD) processes, i.e., accumulative roll bonding and equal-channel angular pressing, was evaluated using scanning transmission electron microscopy/transmission electron microscopy observations. The dislocation density drastically increased from ~ 1013 m− 2 to about 5 × 1014 m− 2, and then saturated, for both SPD processes.