Strength Analyses of FE₂O₃+Al Nanocomposites Using Classical Molecular Dynamics

Classical molecular dynamics (CMD) simulation is an important technique for analyzing custom-designed nanostructured materials and nano-sized systems such as nanowires and nanobelts. This research focuses on analyzing the strength of Fe₂O₃+Al energetic nanocomposites using CMD. A generic potential form is used to describe the behavior of the Fe+Al+Fe₂O₃+Al₂O₃ system. The potential is able to describe bulk single crystal behavior of Fe, Al, Fe₂O₃, Al₂O₃ as well as interfacial transitions among them. The nanostructures analyzed include polycrystalline Aluminum, Fe₂O₃ as well as their composites with two different volume fractions (0.6/0.4 and 04/0.6). The polycrystalline structures are generated using voronoi tessellation. Quasi-static strength analyses are carried out using a massively parallel CMD code for both tension and compression. The analyses reveal that reverse Hall-Petch (H-P) effect is operative for polycrystalline Al under both tension and compression. However, for polycrystalline Fe₂O₃ reverse H-P effect is operative under tension only. Compression still shows direct H-P effect. This effect transcends into the strength of both composites at all grain sizes. In addition, we also observe tension-compression strength asymmetry in the all polycrystalline systems. This framework offers an important tool for nanoscale design of advanced nanocomposite materials.