Columnar grain boundaries are the weakest link in hard coatings: insights from micro-cantilever testing

Yinxia Zhang; Matthias Bartosik; Steffen Brinckmann; Ujival Bansal; Subin Lee; Christoph Kirchlechner

doi:10.1080/21663831.2025.2560526

Columnar grain boundaries are the weakest link in hard coatings: insights from micro-cantilever testing

Yinxia Zhang
, Matthias Bartosik
, Steffen Brinckmann
, Ujival Bansal
, Subin Lee
, Christoph Kirchlechner

Chair of Functional Materials and Materials Systems (425)

Research output: Contribution to journal › Article › Research › peer-review

Abstract

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.

Original language	English
Pages (from-to)	1099-1107
Number of pages	9
Journal	Materials Research Letters [Elektronische Ressource]
Volume	2025
Issue number	Volume 13, Issue 11
DOIs	https://doi.org/10.1080/21663831.2025.2560526
Publication status	Published - 13 Jul 2025

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1080/21663831.2025.2560526

Cite this

@article{06dbe25632464c73a33fc1b963551978,

title = "Columnar grain boundaries are the weakest link in hard coatings: insights from micro-cantilever testing",

abstract = "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.",

author = "Yinxia Zhang and Matthias Bartosik and Steffen Brinckmann and Ujival Bansal and Subin Lee and Christoph Kirchlechner",

year = "2025",

month = jul,

day = "13",

doi = "10.1080/21663831.2025.2560526",

language = "English",

volume = "2025",

pages = "1099--1107",

journal = "Materials Research Letters [Elektronische Ressource]",

issn = "2166-3831",

publisher = "Taylor and Francis",

number = "Volume 13, Issue 11",

}

TY - JOUR

T1 - Columnar grain boundaries are the weakest link in hard coatings

T2 - insights from micro-cantilever testing

AU - Zhang, Yinxia

AU - Bartosik, Matthias

AU - Brinckmann, Steffen

AU - Bansal, Ujival

AU - Lee, Subin

AU - Kirchlechner, Christoph

PY - 2025/7/13

Y1 - 2025/7/13

N2 - 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.

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.

U2 - 10.1080/21663831.2025.2560526

DO - 10.1080/21663831.2025.2560526

M3 - Article

SN - 2166-3831

VL - 2025

SP - 1099

EP - 1107

JO - Materials Research Letters [Elektronische Ressource]

JF - Materials Research Letters [Elektronische Ressource]

IS - Volume 13, Issue 11

ER -