Tensile behaviors of amorphous-ZrCu/nanocrystalline-Cu multilayered thin film on polyimide substrate

The tensile behaviors of the monolithic ZrCu thin film metallic glass, monolithic crystalline Cu thin film, and the ZrCu/Cu multilayered thin films with various individual layered thicknesses deposited on the polyimide foil have been investigated. The modulus and strength of the multilayered thin films are demonstrated to be consistent with the theoretical Rule of Mixture values. As the individual layer thickness decreases from 100 to 10 nm, the Young's moduli are varied slightly. However, the maximum tensile stress exhibits a highest value for the 25 nm layer thickness. The higher crack spacing, or the lower crack density, of this 25 nm multilayer film leads to the highest strength.

► Tensile properties of polyimide-supported ZrCu/Cu multilayer coating were examined.
► Extracted moduli and stresses of thin films are close to the theoretical values.
► The cracks propagate along the domain interfaces of multilayered thin film.
► The 25/25 nm film shows a lower density and higher spacing of surface microcracks.
► Due to the microcrack distribution, the 25/25 nm film shows the highest strength.