Comparative molecular dynamics study of fcc-Ni nanoplate stress corrosion in water

摘要

Reactive molecular dynamics studies of stress corrosion properties of Ni metal nanoplate structures in pressurized water at different temperatures, chemical environments and mechanical boundary conditions have been performed. The results indicate reduction of dislocation nucleation barriers due to the water reactions on material surfaces, simulated loading rate and elevated temperature, resulting in reduction of material strength and ductility. It is also found that pre-oxidized surfaces yield increased initial dislocation nucleation barriers. Likewise, significant effects of stress triaxiality on strength, ductility and surface reactivity are also observed by comparison of boundary conditions. Size dependent structure failure modes and distributions of stress and strain have been explored. A possible Ni dissolution mechanism is identified and validated using DFT calculations and metadynamics simulations.