Strength of nano-twinned gradient nano-grained copper: Molecular dynamic simulation

Molecular dynamics simulations are performed to reveal the underlying deformation mechanisms of gradient nano-grained materials with different-sized twins. The results indicate that the critical twin boundary spacing where the strength begins to soften decreases and the maximum strength of the material increases with the declining of the gradient. Below the critical value, the plastic deformation mechanism is dominated by the partial dislocations paralleling to the twin boundary, but when the twin boundary spacing exceed the critical value, the dislocation moved by the way of intersecting to the twin boundary.