Champs élastiques autour d'un joint de grain : Microdiffraction et dynamique des dislocations – ELASTIC_GB

The mechanical properties of polycrystalline metals with nanometric or ultrafine grains differ dramatically from their bulk counterparts due to grain boundary strengthening effects. They have, therefore, attracted a great deal of interest in the recent years. However, the knowledge of the underlying mechanisms is still incomplete. The miniaturization of microstructures (e.g. the decrease of interconnect sizes in the semiconductor industry, of component sizes in microelectromechanical systems etc.') generates a loss of performance or reliability. The knowledge of mechanical properties of materials at these small scales is then critical for improving the device properties. Modeling size effects and internal length scale associates to grain boundaries in continuous media is a long-standing unsolved problem. For this reason, high resolution measurement (in the sub-micrometer range) of elastic fields are proposed in the vicinity of a grain boundary with X-ray microdiffraction at the ESRF. The latter experiments will be compared with 3D simulations of dislocation dynamics, a sole theoretical tool providing the possibility to account for the discrete nature of plastic déformation at the experiment scale. Finally, a crystalline plasticity model accounting for the information delivered by X-ray microdiffraction experiments and DD simulations will be developed to simulate the mechanical properties of interconnects in semiconductor.