Measuring Nanoscale Stress Intensity Factors with an Atomic Force Microscope

TL;DR

This paper demonstrates a novel method using Atomic Force Microscopy and Digital Image Correlation to measure nanoscale stress intensity factors and surface displacements near crack tips in glass, achieving high spatial resolution.

Contribution

It introduces an integrated digital image correlation technique for quantitative nanoscale stress analysis using AFM images, capable of resolving displacements as small as 10 nm.

Findings

Quantitative measurement of stress intensity factors at the nanoscale.

Surface displacement fields align with linear elastic solutions.

Access to out-of-plane displacement at the crack tip.

Abstract

Atomic Force Microscope images of a crack intersecting the free surface of a glass specimen are taken at different stages of subcritical propagation. From the analysis of image pairs, it is shown that a novel Integrated Digital Image Correlation technique allows to measure stress intensity factors in a quantitative fashion. Image sizes as small as 200 nm can be exploited and the surface displacement fields do not show significant deviations from linear elastic solutions down to a 10 nm distance from the crack tip. Moreover, this analysis gives access to the out-of-plane displacement of the free surface at the crack tip.