Local flow stresses in interpenetrating-phase composites based on nanoporous gold — In situ diffraction

We report a synchrotron in situ diffraction experiment exploring stress evolution during compression of interpenetrating-phase nanocomposites based on nanoporous gold and polymer. While previous experiments provided indirect indication of local flow conditions based on macroscopic effective flow stress and micromechanics models such as Gibson-Ashby scaling law, the lattice parameter data of our experiment access the flow stress directly. At small structure size we find excellent agreement with previous reports, supporting the match between material and model of those studies. Yet, deviations at larger structure size suggest that coarsening generates defects in metal network structure that are ignored by standard models. [Display omitted]