Influence of α-Al2O3 texture on residual stress, cooling cracks and hardness in CVD α-Al2O3/Ti(C,N) coatings on cemented carbide
Sirtuli, Larissa Juliana LU
; Thakare, Amol
; Norgren, Susanne
LU
; Östby, Jonas
and Shoja, Siamak
(2026)
In Surface & Coatings Technology
563.
- Abstract
- CVD α-Al2O3 coatings on cemented carbides are widely used in steel turning, where cutting tool performance is strongly dependent on the crystallographic texture of the α-Al2O3 layer. Residual stress, cooling-crack density, and hardness are key factors influencing coating integrity during machining. Although texture has been reported to affect these properties, trends remain inconsistent in the literature. In this work, three CVD α-Al2O3/Ti(C,N) coatings with identical architecture, substrate, and processing route, but distinct α-Al2O3 textures: i. c-plane (0001), ii. r-plane (011 ̅2), and iii. a-plane (112 ̅0) were investigated to isolate the role of texture under controlled conditions. The (0001) coating exhibited the highest tensile... (More)
- CVD α-Al2O3 coatings on cemented carbides are widely used in steel turning, where cutting tool performance is strongly dependent on the crystallographic texture of the α-Al2O3 layer. Residual stress, cooling-crack density, and hardness are key factors influencing coating integrity during machining. Although texture has been reported to affect these properties, trends remain inconsistent in the literature. In this work, three CVD α-Al2O3/Ti(C,N) coatings with identical architecture, substrate, and processing route, but distinct α-Al2O3 textures: i. c-plane (0001), ii. r-plane (011 ̅2), and iii. a-plane (112 ̅0) were investigated to isolate the role of texture under controlled conditions. The (0001) coating exhibited the highest tensile residual stress and the lowest crack density, while the (011 ̅2) and (112 ̅0) coatings showed lower stresses and denser crack network. This behaviour is consistent with a texture-dependent thermal expansion mismatch, complemented by orientation-dependent stress accommodation during cooling. The (011 ̅2) and (112 ̅0) textures, with a greater in-plane contribution of the c-axis, develop higher intrinsic thermal stress and thus promote more extensive crack formation for stress relaxation compared to (0001) texture. Nanohardness values were comparable across the three textures. The results demonstrate that α-Al2O3 texture has a clear influence on residual stress and cracking, but a limited effect on hardness. These findings provide a more consistent basis for interpreting texture–property relationships and suggest that the performance of (0001)-textured coatings in steel turning is primarily associated with reduced crack density and their response under directional loading, rather than with differences in hardness. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/ced1d322-3bd3-4be0-882f-ddf8e0aa7180
- author
- Sirtuli, Larissa Juliana
LU
; Thakare, Amol
; Norgren, Susanne
LU
; Östby, Jonas
and Shoja, Siamak
- organization
- publishing date
- 2026-09-15
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- CVD coatings, α-Al2O3, Crystallographic texture, Residual stress, Thermal cracks, Nanohardness
- in
- Surface & Coatings Technology
- volume
- 563
- article number
- 133759
- publisher
- Elsevier
- external identifiers
-
- scopus:105044415924
- ISSN
- 0257-8972
- DOI
- 10.1016/j.surfcoat.2026.133759
- language
- English
- LU publication?
- yes
- id
- ced1d322-3bd3-4be0-882f-ddf8e0aa7180
- date added to LUP
- 2026-08-13 09:24:06
- date last changed
- 2026-08-31 19:27:34
@article{ced1d322-3bd3-4be0-882f-ddf8e0aa7180,
abstract = {{CVD α-Al2O3 coatings on cemented carbides are widely used in steel turning, where cutting tool performance is strongly dependent on the crystallographic texture of the α-Al2O3 layer. Residual stress, cooling-crack density, and hardness are key factors influencing coating integrity during machining. Although texture has been reported to affect these properties, trends remain inconsistent in the literature. In this work, three CVD α-Al2O3/Ti(C,N) coatings with identical architecture, substrate, and processing route, but distinct α-Al2O3 textures: i. c-plane (0001), ii. r-plane (011 ̅2), and iii. a-plane (112 ̅0) were investigated to isolate the role of texture under controlled conditions. The (0001) coating exhibited the highest tensile residual stress and the lowest crack density, while the (011 ̅2) and (112 ̅0) coatings showed lower stresses and denser crack network. This behaviour is consistent with a texture-dependent thermal expansion mismatch, complemented by orientation-dependent stress accommodation during cooling. The (011 ̅2) and (112 ̅0) textures, with a greater in-plane contribution of the c-axis, develop higher intrinsic thermal stress and thus promote more extensive crack formation for stress relaxation compared to (0001) texture. Nanohardness values were comparable across the three textures. The results demonstrate that α-Al2O3 texture has a clear influence on residual stress and cracking, but a limited effect on hardness. These findings provide a more consistent basis for interpreting texture–property relationships and suggest that the performance of (0001)-textured coatings in steel turning is primarily associated with reduced crack density and their response under directional loading, rather than with differences in hardness.}},
author = {{Sirtuli, Larissa Juliana and Thakare, Amol and Norgren, Susanne and Östby, Jonas and Shoja, Siamak}},
issn = {{0257-8972}},
keywords = {{CVD coatings; α-Al2O3; Crystallographic texture; Residual stress; Thermal cracks; Nanohardness}},
language = {{eng}},
month = {{09}},
publisher = {{Elsevier}},
series = {{Surface & Coatings Technology}},
title = {{Influence of α-Al2O3 texture on residual stress, cooling cracks and hardness in CVD α-Al2O3/Ti(C,N) coatings on cemented carbide}},
url = {{http://dx.doi.org/10.1016/j.surfcoat.2026.133759}},
doi = {{10.1016/j.surfcoat.2026.133759}},
volume = {{563}},
year = {{2026}},
}