Site dependence of surface dislocation nucleation in ceramic nanoparticles

Abstract The extremely elevated strength of nanoceramics under compression arises from the necessity to nucleate highly energetic dislocations surface, in samples that are too small contain pre-existing defects. Here, we investigate site dependence surface dislocation nucleation MgO nanocubes using a combination molecular dynamics simulations, nudged-elastic-band method calculations and rate theory predictions. Using an original simulation setup, obtain complete mapping potential sites on nanoparticle find that, already at intermediate temperature, not only corners favorable sites, but also edges even regions side surfaces, while other locations intrinsically unfavorable. Results discussed context recent situ TEM experiments, sheding new lights deformation mechanisms happening during ceramic nanopowder compaction sintering processes.