| We briefly review the experimental data and theoretical concepts concerning plastic deformation and fracture processes in nanomaterials with bimodal structures. Special attention is paid to the peculiarities of plastic deformation of these materials that result in the combination of a high flow stress and strain to failure. Also, we suggest a theoretical model that describes the generation of nanoscale cracks at the boundaries between the large grains and nanoscale matrix. In the framework of the model, cracks are generated in the stress field of interfacial disclination dipoles formed at the interfaces between large grains and the nanocrystalline matrix during plastic deformation of nanomaterials with bimodal grain size distributions. The model predicts that the generation of cracks at such disclination dipoles is energetically favorable in metallic and ceramic nanomaterials with bimodal structures in wide ranges of their structural parameters. |
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