Work hardening discrepancy designing to strengthening gradient nanotwinned Cu

Abstract

This study investigates the mechanical behaviors of sandwiched gradient nanotwinned (GNT) Cu designed by only changing the soft component in the central layer with a fixed hard component at its surface. We found that as the work hardening discrepancy of components increases, both the strengthening and work hardening of GNT Cu increase simultaneously, producing a better strength-ductility synergy compared to their freestanding components. The optimized mechanical properties are results of the promoted strain delocalization, prolonged elastic-plastic transition, and larger strain gradient, which induces more geometrically necessary dislocations (GNDs) at the interfaces.