Inverse Bauschinger Effect in Active Ultrastable Glasses

TL;DR

This study reveals that active ultrastable glasses can exhibit reversible and inverse memory effects under shear, with activity-induced shear band networks enabling structural healing and complex mechanical responses.

Contribution

It demonstrates the existence of inverse Bauschinger effects and shear-induced memory in active glasses, highlighting the role of activity in structural and mechanical behavior.

Findings

Active glasses show reversible memory effects under shear.

Inverse Bauschinger effect observed depending on deformation history.

Shear softening leads to stable, less branched networks with cyclic loading.

Abstract

Memory effects in amorphous materials have been widely studied because of their possible widespread future applications. We show here that ultrastable glasses can exhibit a transient reversible memory effect when subjected to both a local driving force via Run-and-tumble active particles and global shear. We investigate the system's response across different yielding regimes by selectively switching the shear direction at different strains. We analyze how changes in shear direction influence yielding, post-yield behavior, and structural evolution in active amorphous solids. Our model active system exhibits an enhanced anisotropic response, displaying both conventional and inverse Bauschinger effects, depending on the deformation history. The results indicate that activity-induced shear band networks create structural memory, enabling the system to heal upon shear reversal due to the transient nature of this phenomenon. Additionally, we observe that shear softening under cyclic loading produces an irreversible, stable, and less branched network structure with increasing cycles. These findings provide novel insights into how activity and shear collectively contribute to mechanical response, including memory formation in ultrastable disordered systems.