Isomorphs in sheared binary Lennard-Jones glass: Transient response.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Studying shear deformation in amorphous solids provides insights into their mechanical behavior.
• Isomorphic state points offer a framework for comparing material properties across different thermodynamic conditions.

Purpose of the Study:

• Investigate the invariance of transient shear stress-strain curves in binary Lennard-Jones glasses along isomorphs.
• Determine how density variations affect the peak stress during shear deformation.

Main Methods:

• Simulated shear deformation of binary Lennard-Jones glasses at various densities and strain rates.
• Identified isomorphs by ensuring invariant reduced steady-state flow stress.
• Analyzed strain profiles and nonaffine motion during transient deformation.

Main Results:

• The peak stress in the stress-strain curves was found to be non-invariant along isomorphs, decreasing with increasing density.
• The tendency to form shear bands varied with density, being strongest at lower densities.
• Steady-state flow stress remained invariant in reduced units along isomorphs.

Conclusions:

• The transient peak stress is sensitive to density changes along isomorphs, unlike the steady-state flow stress.
• Shear banding tendency, influenced by the effective steepness of the potential, underlies the observed changes in peak stress.
• Findings highlight the complex interplay between structure, density, and deformation dynamics in amorphous materials.