Finite Disorder Critical Point in the Brittle-to-Ductile Transition of Amorphous Solids in the Presence of Particle Pinning

TL;DR

This study reveals a finite disorder critical point in amorphous solids where increasing particle pinning induces a transition from brittle to ductile yielding, supported by finite size scaling and correlation with shear band properties.

Contribution

It introduces quenched particle pinning as a new method to control the brittle-to-ductile transition in amorphous solids, establishing a critical point at finite pinning concentration.

Findings

Transition from brittle to ductile yielding with increased pinning

Critical behavior confirmed by finite size scaling

Correlation between shear band width and pinning concentration

Abstract

The mechanical yielding of amorphous solids under external loading can be broadly classified into ductile and brittle types, depending on whether their macroscopic stress response is smooth or abrupt, respectively. Recently, it has been shown that these two regimes, obtained by tuning the degree of annealing of the system, are separated by a critical point at a finite inherent disorder strength. Here, we demonstrate a transition from brittle yielding to ductile yielding by introducing quenched disorder in the form of randomly pinned particles. The well-annealed samples, which exhibit brittle yielding, undergo a transition to increasingly ductile yielding with increasing pinning concentrations while exhibiting an enhanced stress overshoot. Extensive finite size analysis is performed to demonstrate the critical nature of the transition at a finite pinning concentration and the various scaling exponents obtained are found to be in good agreement with the reported values. Finally, we show a direct correspondence with the shear band width and the critical pining concentration to establish a possible connection between inherent disorder strength and quenched disorder strength due to particle pinning.