Ductile-brittle transition of open-cell nanoporous Cu in tension: A reliance of specific surface area

Abstract

We report the ductile-brittle transitions and their reliances on specific surface area (γ), for the bi-continuous and open-cell nanoporous (NP) Cu in tension, using molecular dynamics simulations. With an increase of γ, NP Cu undergo the first ductile-to-brittle (γ≤ 2.13 nm−1) and subsequent brittle-to-ductile (γ > 2.13 nm−1) transitions. Two different plasticity modes are governing such two ductile-brittle transitions: dislocation activities inhibition for the former and dislocation networks formation contributes to the latter. Serving as the origin of dislocations/stacking faults, the surface characteristic plays a key role in such ductile-brittle transition and deformation modes.