Multiresolution molecular-dynamics (MRMD) approach for multimillion atom simulations has been used no investigate structural properties, mechanical failure in nanostructured materials, and atomic-level stresses in nanoscale semiconductor/ceramic mesas. Structural transformations under pressure for gallium arsenide and silicon carbide in bulk and nanocrystalline forms are studied. Crack propagation and fracture in silicon nitride, silicon carbide, gallium arsenide, and nanophase ceramics are investigated. We observe a crossover from slow to rapid fracture and a correlation between the speed of crack propagation and morphology of fracture surface. Results of multimillion atom simulations of mechanical behavior of the Si(111)/Si_3N_4(0001) interface, atomic-level stresses in Si(111)/Si_3N_4(0001) and Si(111)/a-Si_3N_4 nanopixels, and nanoindentation of crystalline and amorphous Si_3N_4 films using a rigid, pyramidal indenter will be discussed. Oxidation of aluminum nanoclusters is also investigated with a parallel molecular-dynamics approach based on dynamic charge transfer among atoms.
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