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

Abstract

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.

The ReaxFF reactive force-field: development, applications and future directions

“…32,33 Typically these sets began as non-transferable ReaxFF descriptions constituting independent development branches, but many have later been merged, through extensive refitting, with the combustion (C/B/N/H/O) 34 or aqueous branches (Ni/C/H/O). [35][36][37] It is worth mentioning that the popular ReaxFF high-energy material description 4,5,[38][39][40][41][42][43][44] is older than the combustion branch, but was recently merged-without an obvious loss in accuracy-with this branch. 39,45 Notable developments on the aqueous branch include water-liquid and proton/anion transfer extensions to a range of transition metals and metal oxides (Fe/Ni/Cu/Zn/Al/Ti/ Ca/Si), 7,15,19,35,46-52 along with C/H/O/N/S/P developments aimed at biomolecules and their interactions with inorganic interfaces.…”

“…[35][36][37] It is worth mentioning that the popular ReaxFF high-energy material description 4,5,[38][39][40][41][42][43][44] is older than the combustion branch, but was recently merged-without an obvious loss in accuracy-with this branch. 39,45 Notable developments on the aqueous branch include water-liquid and proton/anion transfer extensions to a range of transition metals and metal oxides (Fe/Ni/Cu/Zn/Al/Ti/ Ca/Si), 7,15,19,35,46-52 along with C/H/O/N/S/P developments aimed at biomolecules and their interactions with inorganic interfaces. [53][54][55][56][57][58][59][60] Comparison to similar methods Although in this article we focus almost exclusively on ReaxFF and its applications, the ReaxFF method is not unique in its aim: to provide a simulation environment for describing the dynamics of chemical reactions at an atomistic scale with significantly fewer computational resources compared with QM.…”

Investigation of chloride-induced depassivation of iron in alkaline media by reactive force field molecular dynamics

“…ReaxFF-MD simulations were performed using the Large-scale Atomistic/ Molecular Massively Parallel Simulator (LAMMPS) framework 60 and the Extreme Science and Engineering Discovery Environment (XSEDE). 61 The ReaxFF framework was based on the interatomic potential theory developed by van Duin et al 62 The detailed explanation of the framework is provided by van Duin et al 33,36,40,42,58,63,64 The specific ReaxFF parameters for iron and other interacting species (e.g., Na, O, H, and Cl) were obtained from the works of Aryanpour et al, 34 Rahaman et al, 65 and Psofogiannakis et al, 64 who developed parameters to model ironoxyhydroxide systems, chloride-water and copper chloride-water systems, and hydration of zeolite, respectively. We validated these parameters (that are required for determining the bond order, bond energy, valence angle energy, torsional angle energy, and van der Waals energy) by comparing ReaxFF-MD simulations of the surface formation energy and water adsorption energy on the Fe(110) surface with DFT calculations.…”

“…Atomistic modeling techniques, such as reactive force field molecular dynamics (ReaxFF-MD) [33][34][35][36][37][38][39][40][41][42] and density functional theory (DFT), [43][44][45][46][47][48] have shown great potential to provide answers to such questions. In particular, ReaxFF-MD has emerged as a simulation framework to investigate reactive processes at spatial scales of nm 2 that can be correlated to physical systems.…”

Benchmarking the Performance of the ReaxFF Reactive Force Field on Hydrogen Combustion Systems

“…ReaxFF potentials have been developed and applied to combustion reactions, [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] including hydrocarbons, hydrogen, 54,63 and syngas. 67 The ReaxFF method has also been extensively applied to material science, [68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83] catalysis, [84][85][86][87][88] and other chemical systems. 39,[89][90][91][92][93][94][95][96]…”