Effect of substrate bias voltage on the mechanical properties and deformation mechanisms in the nanostructured Ti-22Nb-10Zr coating
Effect of substrate bias voltage on the mechanical properties and deformation mechanisms in the nanostructured Ti-22Nb-10Zr coating
The manufacturing of future implants based on NiTi shape memory alloys, like stents, orthodontic archwires, intracranial aneurysms…, clips aims to eliminate the cytotoxicity and allergic problems associated with the release of nickel ions. In this context, the design of β-rich Ti-22Nb-10Zr (mass.%) coating by magnetron sputtering, with a non-linear elastic behavior and tunable mechanical properties, offers a novel approach for the development of a new biocompatible implants with self-adjusting mechanical properties. The XRD and TEM analyses reveal that microstructure consisting of hexagonal close-packed (α-phase), prevalent body-centered cubic (β-phase) and orthorhombic (α″-phase) nanograins, which can be tuned during the deposition by a single parameter – applied bias voltage as a result of the activation of a stress-induced martensitic transformation (β → α″). We found that the minimum stress value to trigger the SIM transformation must be higher than 712 MPa (bias −63 V). The application of higher bias voltage values alters the main deformation mechanism, from a combination of reversible SIM transformation and mechanical twinning to dislocation slip, causing the compressive residual stresses to decrease from 712 to 120 MPa, the hardness increases from 2,1 to 4,1 GPa, and the coating stops showing low Young's modulus (<50 GPa) and non-linear elastic behavior.
Deformation mechanisms, Load-bearing transfer applications, Martensitic phase transformation, Nano-mechanical characterization, Residual stresses, β-Rich Ti alloys
Frutos, E.
8730c6ea-7f59-44b7-aa33-cfee57de8b25
Karlik, M.
df29ecf1-6f1e-4713-a15a-82b321804596
Jiménez, J. A.
68c16378-e201-433c-acc7-86995218c32d
Polcar, T.
c669b663-3ba9-4e7b-9f97-8ef5655ac6d2
15 January 2021
Frutos, E.
8730c6ea-7f59-44b7-aa33-cfee57de8b25
Karlik, M.
df29ecf1-6f1e-4713-a15a-82b321804596
Jiménez, J. A.
68c16378-e201-433c-acc7-86995218c32d
Polcar, T.
c669b663-3ba9-4e7b-9f97-8ef5655ac6d2
Frutos, E., Karlik, M., Jiménez, J. A. and Polcar, T.
(2021)
Effect of substrate bias voltage on the mechanical properties and deformation mechanisms in the nanostructured Ti-22Nb-10Zr coating.
Surface and Coatings Technology, 405, [126674].
(doi:10.1016/j.surfcoat.2020.126674).
Abstract
The manufacturing of future implants based on NiTi shape memory alloys, like stents, orthodontic archwires, intracranial aneurysms…, clips aims to eliminate the cytotoxicity and allergic problems associated with the release of nickel ions. In this context, the design of β-rich Ti-22Nb-10Zr (mass.%) coating by magnetron sputtering, with a non-linear elastic behavior and tunable mechanical properties, offers a novel approach for the development of a new biocompatible implants with self-adjusting mechanical properties. The XRD and TEM analyses reveal that microstructure consisting of hexagonal close-packed (α-phase), prevalent body-centered cubic (β-phase) and orthorhombic (α″-phase) nanograins, which can be tuned during the deposition by a single parameter – applied bias voltage as a result of the activation of a stress-induced martensitic transformation (β → α″). We found that the minimum stress value to trigger the SIM transformation must be higher than 712 MPa (bias −63 V). The application of higher bias voltage values alters the main deformation mechanism, from a combination of reversible SIM transformation and mechanical twinning to dislocation slip, causing the compressive residual stresses to decrease from 712 to 120 MPa, the hardness increases from 2,1 to 4,1 GPa, and the coating stops showing low Young's modulus (<50 GPa) and non-linear elastic behavior.
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More information
Accepted/In Press date: 21 November 2020
e-pub ahead of print date: 25 November 2020
Published date: 15 January 2021
Additional Information:
Funding Information:
E.F. and T.P. wants to express their gratitude to the Czech Science Foundation and Engineering and Physical Sciences Research Council for funding received through the projects 14-32801P and EP/K005103/1 , respectively. Furthermore, E.F. wants to give thanks to the program COMPETE - Programa Operacional Factores de Competitividade: POCI-01-0145-FEDER-030416- and by national funds through FCT – Fundacao para a Ciencia e a Tecnologia -, under the project UIDB/00285/2020, and to CENIM's X-ray laboratory for the support given on the analysis of XRD patterns. Finally, M.K. and T.P. would like to acknowledge the financial support of the European Regional Development Fund in the frame of the projects No. CZ.02.1.01/0.0/0.0/15-003/0000485 and CZ.02.1.01/0.0/0.0/16-019/0000778 , respectively.
Publisher Copyright:
© 2020 Elsevier B.V.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
Keywords:
Deformation mechanisms, Load-bearing transfer applications, Martensitic phase transformation, Nano-mechanical characterization, Residual stresses, β-Rich Ti alloys
Identifiers
Local EPrints ID: 454835
URI: http://eprints.soton.ac.uk/id/eprint/454835
ISSN: 0257-8972
PURE UUID: 98b1e70b-ef8f-47da-8f1c-7abf90ca71f0
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Date deposited: 24 Feb 2022 21:55
Last modified: 06 Jun 2024 01:49
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Author:
E. Frutos
Author:
M. Karlik
Author:
J. A. Jiménez
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