Microscale bending plasticity and fracture behavior of amorphous aluminum oxide films

Fuente: arXiv
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Hauptverfasser: Mathews, Nidhin George, Frankberg, Erkka J., Devulapalli, Vivek, Kumar, Chandan, Putz, Barbara, Lambai, Aloshious, Khakalo, Sergei, Cabrioli, Mattia, Christensen, Bjarke Holl, Niemelä, Janne-Petteri, Müller, Arnold Milenko, Di Fonzo, Fabio, Utke, Ivo, Levänen, Erkki, Mohanty, Gaurav
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Veröffentlicht: 2026
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author Mathews, Nidhin George
Frankberg, Erkka J.
Devulapalli, Vivek
Kumar, Chandan
Putz, Barbara
Lambai, Aloshious
Khakalo, Sergei
Cabrioli, Mattia
Christensen, Bjarke Holl
Niemelä, Janne-Petteri
Müller, Arnold Milenko
Di Fonzo, Fabio
Utke, Ivo
Levänen, Erkki
Mohanty, Gaurav
author_facet Mathews, Nidhin George
Frankberg, Erkka J.
Devulapalli, Vivek
Kumar, Chandan
Putz, Barbara
Lambai, Aloshious
Khakalo, Sergei
Cabrioli, Mattia
Christensen, Bjarke Holl
Niemelä, Janne-Petteri
Müller, Arnold Milenko
Di Fonzo, Fabio
Utke, Ivo
Levänen, Erkki
Mohanty, Gaurav
contents Recent work has demonstrated microscale compressive plasticity in pulse laser deposited (PLD) amorphous alumina (a-Al2O3). This work explores microscale bending plasticity and fracture behavior of a-Al2O3 films deposited using three different methods-PLD, atomic layer deposition (ALD) and sputter deposition (SD). The three deposition routes produced amorphous films with similar stoichiometric compositions. We demonstrate, for the first time, bending plasticity in PLD and ALD a-Al2O3 films at microscale using in situ microcantilever bending experiments at room temperature. All tested PLD a-Al2O3 microcantilevers showed substantial ductile behavior in bending by accommodating total strains >10% without fracture. Half of the tested ALD a-Al2O3 cantilevers exhibited elastic brittle fracture while the other half showed bending plasticity, indicating that the observed deformation behavior is strongly influenced by the presence and distribution of defects within the tested volume. All SD a-Al2O3 microcantilevers showed elastic brittle failure attributed to their columnar growth microstructure. The microscale bending response was found to be highly dependent on the film deposition method highlighting the role of defects in suppressing plasticity mechanisms. Notched microcantilever bending tests on all three films showed brittle failure with similar fracture toughness value of 3.1 +/- 0.2 MPa.m0.5, effectively ruling out any localized crack tip plasticity. These findings underscore the importance of minimizing defects during fabrication in order to develop damage tolerant amorphous oxides. Nonetheless, the observation of bending plasticity in both PLD and ALD microcantilevers, which include a tensile stress component as well, suggests that the plastic deformation mechanisms in amorphous alumina are more general and are not exclusively governed by the deposition method.
format Preprint
id arxiv_https___arxiv_org_abs_2605_01917
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Microscale bending plasticity and fracture behavior of amorphous aluminum oxide films
Mathews, Nidhin George
Frankberg, Erkka J.
Devulapalli, Vivek
Kumar, Chandan
Putz, Barbara
Lambai, Aloshious
Khakalo, Sergei
Cabrioli, Mattia
Christensen, Bjarke Holl
Niemelä, Janne-Petteri
Müller, Arnold Milenko
Di Fonzo, Fabio
Utke, Ivo
Levänen, Erkki
Mohanty, Gaurav
Materials Science
Recent work has demonstrated microscale compressive plasticity in pulse laser deposited (PLD) amorphous alumina (a-Al2O3). This work explores microscale bending plasticity and fracture behavior of a-Al2O3 films deposited using three different methods-PLD, atomic layer deposition (ALD) and sputter deposition (SD). The three deposition routes produced amorphous films with similar stoichiometric compositions. We demonstrate, for the first time, bending plasticity in PLD and ALD a-Al2O3 films at microscale using in situ microcantilever bending experiments at room temperature. All tested PLD a-Al2O3 microcantilevers showed substantial ductile behavior in bending by accommodating total strains >10% without fracture. Half of the tested ALD a-Al2O3 cantilevers exhibited elastic brittle fracture while the other half showed bending plasticity, indicating that the observed deformation behavior is strongly influenced by the presence and distribution of defects within the tested volume. All SD a-Al2O3 microcantilevers showed elastic brittle failure attributed to their columnar growth microstructure. The microscale bending response was found to be highly dependent on the film deposition method highlighting the role of defects in suppressing plasticity mechanisms. Notched microcantilever bending tests on all three films showed brittle failure with similar fracture toughness value of 3.1 +/- 0.2 MPa.m0.5, effectively ruling out any localized crack tip plasticity. These findings underscore the importance of minimizing defects during fabrication in order to develop damage tolerant amorphous oxides. Nonetheless, the observation of bending plasticity in both PLD and ALD microcantilevers, which include a tensile stress component as well, suggests that the plastic deformation mechanisms in amorphous alumina are more general and are not exclusively governed by the deposition method.
title Microscale bending plasticity and fracture behavior of amorphous aluminum oxide films
topic Materials Science
url https://arxiv.org/abs/2605.01917