Strengthening Mechanisms and Dislocation Dynamics in Twinned Metal Nanowires

摘要

Microtwins are frequently observed in face-centered-cubic (fcc) metal nanowires with low stacking fault energy. The authors have previously reported that the tensile yield strength of copper nanowires can be increased by the presence of twin boundaries. In this work simulations are carried out under both uniaxial tension and compression loading, to demonstrate that the strengthening effects are inherent to these nanowires, independent of the loading condition (tensile/compres-sive). It appears that the strengthening mechanism of the twinned nanowires can be attributed to stress redistribution due to the change of crystallographic orientations across twin boundaries, which requires larger external stress to make them yield as compared to the twin-free wire.