Work hardening in rolled nanolayered metallic composites

The strength of room temperature rolled sputter deposited nanolayered Cu-Nb composites is evaluated. Self-supported Cu-Nb foils with initial individual layer thickness varying from 32 to 75 nm were rolled to the same final layer thickness of 30 nm. Nanoindentation hardness measurements were used to study the change in hardness with rolling strain. The resulting work hardening rate is compared to bulk Cu and mechanisms that give rise to work hardening in nanolayered metals, in the absence of dislocation cell structure formation, are discussed.