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Abstract
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The paper investigates the relation between surface oxidation kinetics and the mechanical properties of iron nanowires with varying sizes, temperatures, and point defects through a reactive molecular dynamics simulation. Deployment of the ReaxFF force field enables realistic simulation of oxygen interactions and growth of the oxide layer, and thus the resultant core-shell (FexOy) nanostructures. Computational validation is ensured via comparison of computed data against experimental results for different loading cases. Results indicate that the diameter of the nanowire, temperature, and density of surface defects significantly influence oxidation progress and mechanical response behavior. Analysis of the radial distribution function confirms enhanced lattice disordering and phase transformation with oxidation. More slender nanowires exhibit increased oxidation kinetics with corresponding embrittlement, while larger-diameter nanowires retain superior ductility under moderate conditions of oxidation. Increased thermal conditions accelerate oxidation processes, featuring quantifiable decreases in elastic modulus and ultimate strength. Deliberate introduction of defects halts dislocation nucleation and interface failure processes, leading to degradation of yield strength. The results provide prescriptive data for oxidation-resistant nanowire structure design via optimization of synthesis protocols, thermal treatment, and defect control techniques.
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