Perfectly plastic flow in silica glass

G. Kermouche (1, 2, 3) , G. Guillonneau (4) , J. Michler (4) , J. Teisseire (5) , E. Barthel (6)

1 University of Lyon
2 Mines Saint-Étienne MSE - École des Mines de Saint-Étienne
3 LGF-ENSMSE - Laboratoire Georges Friedel
4 EMPA - Swiss Federal Laboratories for Materials Science and Technology [Thun]
5 SVI - Surface du Verre et Interfaces
6 SIMM - Sciences et Ingénierie de la Matière Molle

The plastic behavior of silicate glasses has emerged as a central concept for the understanding of glass strength. Here we address the issue of shear-hardening in amorphous silica. Using in situ SEM mechanical testing with a high stiffness device, we have been able to compress silica pillars to large strains while directly monitoring radial strain. The sizeable increase of pillar cross-section during compression directly demonstrates the significant role of homogeneous shear flow. From the direct evaluation of the cross section, we have also measured true stress-strain curves. The results demonstrate that silica predominantly experiences plastic shear flow but that there is no shear-induced hardening. The consequence of this finding for our understanding of glass strength is discussed.

Mots clés: Amorphous silica; Micropillars; Densification; Shear flow; Fracture; In situ testing; Finite element analysis

Domaines: Matière Condensée [cond-mat]; Physique [physics]

G. Kermouche, G. Guillonneau, J. Michler, J. Teisseire, E. Barthel. Perfectly plastic flow in silica glass. Acta Materialia, 2016, 114, pp.146 - 153. ⟨10.1016/j.actamat.2016.05.027⟩. ⟨hal-01393682⟩