TY  - JOUR
AU  - Okotete, Eloho
AU  - Muslija, Alban
AU  - Hohmann, Judith K.
AU  - Kohl, Manfred
AU  - Brinckmann, Steffen
AU  - Lee, Subin
AU  - Kirchlechner, Christoph
TI  - Enhanced crack stability in micro scale fracture testing via optimized bridge notches
JO  - Materials science & engineering / A
VL  - 939
SN  - 0921-5093
CY  - Amsterdam
PB  - Elsevier
M1  - FZJ-2025-04115
SP  - 148479 -
PY  - 2025
AB  - In micro cantilever fracture, a bridge notch geometry with material ligaments at the notch ends helps to reduce focused ion beam artefacts near the notch root by arresting initial cracks and promoting fracture from sharp, natural cracks. Thus, it significantly reduces the statistical scatter in fracture toughness, a common but undesirable feature in micro fracture testing. Although this concept has been validated in simulations and experiments, systematic investigations into the optimal geometry remain lacking. In this study, we experimentally examine the influence of bridge width and notch depth on the fracture toughness of micro cantilevers, using single crystalline silicon as a model material. We found that samples with thinner material bridges and deeper notches exhibit crack arrest before failure, while those with thicker bridges do not show crack arrest instead exhibit apparent toughening. Cantilevers with an optimized bridge notch geometry for crack arrest exhibit a KIC of 1.09 ± 0.02 MPa m0.5, which agrees with previously reported fracture toughness for the Si (111) surface. Additionally, discrepancies between the bridge geometry in the experiment and the ideal structure resulted in a mismatch between the predicted and observed notch requirements for crack arrest. Our findings offer practical guidelines for designing bridge notch geometries to promote bridge failure, thus improving statistical analysis in micro fracture.
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1016/j.msea.2025.148479
UR  - https://juser.fz-juelich.de/record/1047158
ER  -