Fracture of glassy materials as detected by real-time Atomic Force Microscopy (AFM) experiments

TL;DR

This study investigates the fracture behavior of glassy materials at the nanoscale using real-time AFM, revealing a nano-ductile fracture mode involving cavity nucleation and growth, with implications for understanding glass failure.

Contribution

It introduces the first real-time observation of nanometric damage cavities in glass fracture, highlighting a nano-ductile fracture mechanism.

Findings

Crack propagation involves nucleation, growth, and coalescence of nanometric cavities.

Heterogeneities influence crack velocity and behavior.

Nano-ductile fracture mode observed in glassy materials.

Abstract

We have studied the low speed fracture regime for different glassy materials with variable but controlled length scales of heterogeneity in a carefully mastered surrounding atmosphere. By using optical and atomic force (AFM) microscopy techniques we tracked in real-time the crack tip propagation at the nanometer scale on a wide velocity range (1 mm/s and 0.1 nm/s and below). The influence of the heterogeneities on this velocity is presented and discussed. Our experiments revealed also -for the first time- that the crack advance proceeds through nucleation, growth and coalescence of nanometric damage cavities inside the amorphous phase, which generate large velocity fluctuations. The implications of the existence of such a nano-ductile fracture mode in glass are discussed.