TY  - JOUR
AU  - Zhang, Yinxia
AU  - Bartosik, Matthias
AU  - Brinckmann, Steffen
AU  - Bansal, Ujjval
AU  - Lee, Subin
AU  - Kirchlechner, Christoph
TI  - Columnar grain boundaries are the weakest link in hard coatings: insights from micro-cantilever testing
JO  - Materials Research Letters
VL  - 13
IS  - 11
SN  - 2166-3831
CY  - London [u.a.]
PB  - Taylor & Francis
M1  - FZJ-2025-04117
SP  - 1099-1107
PY  - 2025
AB  - The effect of columnar grain boundaries (GBs) on the fracture toughness was investigated using micro-cantilever fracture testing in a hard coating featuring two distinct microstructures within a single sample: a columnar-grained top and an epitaxial bottom region. Bridge-notch fracture initiated more readily in the columnar-grained region, indicating reduced toughness. Furthermore, quantitative analysis of the load drops at bridge-failure confirmed a ∼30% decrease in fracture toughness due to GBs: from 4.1 to 3.0 MPa m1/2. These results reveal the detrimental role of GBs in fracture toughness and highlight the importance of microstructural design for improving the mechanical performance of hard coatings.
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1080/21663831.2025.2560526
UR  - https://juser.fz-juelich.de/record/1047160
ER  -