Interfacial stress transfer mechanism of Cu-Zr amorphous films on polyimide substrates: Effect of deformation-induced devitrification

The fragmentation and interfacial stress transfer of Cu75Zr25 amorphous films with varying film thickness (h) on polyimide substrates were systematically investigated by using uniaxial tensile testing, in combination with in situ optical microscope and atomic force microscope characterizations. It is revealed that the interfacial stress transfer length increases monotonically as h increases. The interfacial stress transfer mechanism changes from elastic-plastic to approximately linear elastic at a critical point of h = 250 nm. This is related to h-dependent deformation-induced devitrification (DID) near the interfaces that the thinner Cu-Zr amorphous films display more DID. This study elucidates for the first time the effect of DID on the interfacial stress transfer, which will be helpful to design the interface with desired property for nanotechnological applications.