Multimillion Atom Simulations of Nanostructured Materials on Parallel Computers Sintering and Consolidation, Fracture

Multiresolution molecular-dynamics approach for multimillion atom simulations has been used to investigate structural properties, mechanical failure in ceramic materials, and atomic-level stresses in nanoscale semiconductor/ceramic mesas (Si/Si3N4). Crack propagation and fracture in silicon nitride, silicon carbide, gallium arsenide, and nanophase ceramics are in-vestigated. We observe a crossover from slow to rapid fracture and a correlation between the speed of crack propagation and morphology of fracture surface. A 100 million atom simulation is carried out to study crack propagation in GaAs. Mechanical failure in the Si/Si3N4 interface is studied by applying tensile strain parallel to the interface. Ten million atom molecular dynamics simulations are performed to determine atomic-level stress distri-butions in a 54 nm nanopixel on a 0.1µm silicon substrate. Multimillion atom simulations of oxidation of aluminum nanoclusters and nanoindentation in silicon nitride are also discussed. Advanced materials with nanometer grain sizes are being developed to achieve higher strength and toughness. 1) Below 100 nm, however, continuum description of materials and devices must be supplemented by atomistic models. This is becaus