Strain rate sensitive stretchability and fracture behavior of nanocrystalline Cu films on flexible substrate

The strain rate dependent stretchability and fracture behavior of the polymer-supported Cu films was studied by uniaxial tension test. The crack spacing of the films is dependent not only upon the strain rate but also the thickness of the films. At a high strain rate, cracks parallel to loading direction are found to occur more easily in thicker film than thinner one. Delamination and crack along loading direct facilitate each other, accelerating the failure of films. The calculated energy release rate decreases with increasing strain rate, which can be used to explain fracture behavior of film/substrate.