Twinning-assisted void initiation and crack evolution in Cu thin film: An in situ TEM and molecular dynamics study

A twinning-induced void initiation mechanism at grain boundary is revealed in Cu through in situ tensile tests. Two microcracks connected by a twin boundary (TB) are formed following the growth of the void, which then develop via the relative sliding of the two crystals beside the migrating TB. The experimental observations of TB migration and dislocation activities are corroborated by performing molecular dynamics simulations.