Hardness and toughness of sodium borosilicate glasses via Vickers's indentations

Marina Barlet (1, 2) , Jean-Marc Delaye (3) , Thibault Charpentier (4) , Mickael Gennisson (3) , Daniel Bonamy (1, 2) , Tanguy Rouxel (5) , Cindy Rountree (1, 6)

1 SPHYNX - Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes
2 SPCSI - Service de Physique et de Chimie des Surfaces et Interfaces
3 SECM - Service d'Etudes du Comportement des Matériaux de Conditionnement
4 LSDRM - Laboratoire Structure et Dynamique par Résonance Magnétique (LCF)
5 IPR - Institut de Physique de Rennes
6 SPEC - UMR3680 - Service de physique de l'état condensé

This study investigates the mechanical response of sodium borosilicate (SBN) glasses as a function of their chemical composition. Vickers's indentation tests provide an estimate of the material hardness (H V) and indentation fracture toughness (K C VIF) plus the amount of densification/shear flow processes. Sodium content significantly impacts the glass behavior under a sharp indenter. Low sodium glasses maintain high connected networks and low Poisson's ratios (ν). This entails significant densification processes during deformation. Conversely, glasses with high sodium content, i.e. large ν, partake in a more depolymerized network favoring deformation by shear flow. As a consequence , indentation patterns differ depending on the processes occurring. Densification processes appear to hinder the formation of halfpenny median–radial cracks. Increasing ν favors shear flow and residual stresses enhance the development of halfpenny median–radial cracks. Hence, K C VIF decreases linearly with ν.

Mots clés: Hardness; Sodium borosilicate glasses; Glass structure; Fracture toughness

Domaines: Physique [physics]

Marina Barlet, Jean-Marc Delaye, Thibault Charpentier, Mickael Gennisson, Daniel Bonamy, et al.. Hardness and toughness of sodium borosilicate glasses via Vickers's indentations. Journal of Non-Crystalline Solids, 2015, 417-418, pp.66-79. ⟨10.1016/j.jnoncrysol.2015.02.005⟩. ⟨cea-01366698⟩