Sommaire:

Most solids like metals and ceramics are polycrystals, i.e. aggregates of crystalline grains separated by 2D defects, grain boundaries (GBs). Although GB sliding is believed to be involved in the irreversible deformation (plasticity) of polycrystalline solids, the microscopic mechanisms at play are still poorly understood, partly because common techniques for atomic polycrystals visualization preclude any information on their dynamics under stress. We propose a colloidal analog of atomic polycrystals obtained by doping a copolymer micellar crystal with nanoparticles and for which the grain size is tuned by changing the crystallization rate. First, we characterize its structure at rest by neutron and light scattering. Second, in order to investigate the plasticity of the colloidal polycrystals, dynamic light scattering measurements on the sample submitted to cyclic deformation are performed using a novel light scattering apparatus specifically designed to access the dynamics of the GBs.

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