Hardening mechanisms and deformation stages in nanograined polycrystals

Strain hardening of nanograined polycrystals is studied using copper-based alloys as an example. The stages of strain hardening are compared for these alloys and for pure metals (copper, gold) having a similar grain size in the range 40–200 nm. The stress σ-strain ɛ dependence demonstrates that the strain hardening of these polycrystalline nanograined materials proceeds, as a rule, in three stages with different hardening mechanisms.