SEM In situ study on deformation behavior of Cu and Cu/Ni films under three-point bending

The deformation and failure of Cu and Cu/Ni film/substrate structure were studied by the scanning electron microscope (SEM) in situ observation under three-point bending. It was found that the rapid deformation occurred at sites near to the interface of film/substrate in Cu and Cu/Ni films. The transferring of deformation finally caused the surface wrinkle. The wrinkle stress can be expressed as sigma(f =)(w) .k(EfE(s)(2)1/3) Based on the results in mesoscale, a simple failure mechanism of films/substrate structure is suggested to understand the transferring process of deformation and failure characteristics.