Departmental Papers (CBE)

Document Type

Journal Article

Date of this Version

12-23-2014

Publication Source

Proceedings of the National Academy of Sciences

Volume

111

Issue

51

Start Page

18167

Last Page

18172

DOI

10.1073/pnas.1413900111

Abstract

We study the uniaxial compressive behavior of disordered colloidal free-standing micropillars composed of a bidisperse mixture of 3- and 6-μm polystyrene particles. Mechanical annealing of confined pillars enables variation of the packing fraction across the phase space of colloidal glasses. The measured normalized strengths and elastic moduli of the annealed freestanding micropillars span almost three orders of magnitude despite similar plastic morphology governed by shear banding. We measure a robust correlation between ultimate strengths and elastic constants that is invariant to relative humidity, implying a critical strain of ∼0.01 that is strikingly similar to that observed in metallic glasses (MGs) [Johnson WL, Samwer K (2005) Phys Rev Lett 95:195501] and suggestive of a universal mode of cooperative plastic deformation. We estimate the characteristic strain of the underlying cooperative plastic event by considering the energy necessary to create an Eshelby-like ellipsoidal inclusion in an elastic matrix. We find that the characteristic strain is similar to that found in experiments and simulations of other disordered solids with distinct bonding and particle sizes, suggesting a universal criterion for the elastic to plastic transition in glassy materials with the capacity for finite plastic flow.

Copyright/Permission Statement

© 2014 National Academy of Sciences.

Keywords

plasticity in disordered solids, shear transformation, cooperative deformation, Eshelby inclusion, colloidal glasses

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Date Posted: 25 October 2017

This document has been peer reviewed.