Non-equibiaxial deformation of W/Cu nanocomposite thin films on stretchable substrate: Effect of loading path

•Non-equibiaxial tensile tests are performed on metallic film-substrate composite.•Two different loading paths have been performed.•Applied strains are measured in situ by X-ray diffraction and image correlation.•Lattice strain and elastic stress–true strain curves are plotted.•The different mechanical behaviours in the two directions of applied load are revealed.

In situ biaxial tensile tests were carried out on W/Cu nanocomposite thin films deposited on a polyimide cruciform substrate. A biaxial testing machine developed on the DiffAbs beamline at the French SOLEIL synchrotron allows for scrutinizing the mechanical behaviour of crystalline thin films at the micro-scale and the macro-scale using simultaneously synchrotron X-ray diffraction and digital image correlation techniques. Both strain analyses have been performed for two controlled non-equibiaxial loading paths: loading ratios of 0.8 and 0.33. The mechanical response is analysed and compared for the two loading ratios.