Strength and strain hardening behavior of Cu-based bilayers and trilayers

Strain hardening in metallic multilayers is shown experimentally to be greater in trilayer films of Cu–Ni–Nb than bilayer films of Cu–Ni or Cu–Nb using both direct measurements of flow strength at different effective strains and an analysis of the out-of-plane deformation around nanoindentation impressions. The mechanism that accounts for increased strain hardening in the trilayer is a proposed super-threader dislocation and cross-slip mechanism, modeled using three-dimensional dislocation dynamics simulations.