Atomistic simulation of creep in a nanocrystal

Area of Science:

• Materials Science
• Computational Physics
• Nanotechnology

Background:

• Understanding stress relaxation in nanocrystals is crucial for materials design.
• Nanoscale microstructure imperfections significantly impact macroscopic material properties.
• Current simulation methods often struggle to capture long-term relaxation dynamics.

Purpose of the Study:

• To develop and present a novel simulation method for macroscopic stress relaxation in atomistic nanocrystal models.
• To investigate the influence of nanoscale microstructure imperfections on anelastic relaxation.
• To establish a link between localized atomic displacements and system-level relaxation behavior.

Main Methods:

• Utilized a metadynamics algorithm for transition state pathway sampling.
• Simulated stress relaxation in an atomistic nanocrystal model under imposed strain.
• Analyzed the correlation between system-level relaxation and localized atomic displacements near defects.

Main Results:

• Successfully simulated the full evolution of classical anelastic relaxation events.
• Demonstrated that relaxation times are governed by nanoscale microstructure imperfections.
• Revealed a direct correlation between macroscopic relaxation and localized atomic displacements at nanostructured defects.

Conclusions:

• The study implies a unit mechanism for self-organized plastic response in nanocrystals.
• Probing stress relaxation variations provides mechanistic insights into material behavior.
• This method enables characterization of microstructure imperfections and matching them to predictive simulations.