Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium

In recent years there are growing interest in fabrication of bulk nanostructured metals and alloys by using severe plastic deformation (SPD) techniques as new alternative in producing bulk nanocrystalline materials. These techniques allows for processing of bulk, fully dense workpiece with ultrafine...

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Main Authors:	Awang Shri, Dayangku Noorfazidah, Tsuchiya, Koichi, Yamamoto, Akiko
Format:	Conference or Workshop Item
Language:	English
Published:	AIP Publishing LLC. 2017
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://umpir.ump.edu.my/id/eprint/20913/ http://umpir.ump.edu.my/id/eprint/20913/ http://umpir.ump.edu.my/id/eprint/20913/1/Corrosion%20behavior%20of%20HPT-deformed%20TiNi%20alloys.pdf

id	ump-20913
recordtype	eprints
spelling	ump-209132018-07-10T07:10:30Z http://umpir.ump.edu.my/id/eprint/20913/ Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium Awang Shri, Dayangku Noorfazidah Tsuchiya, Koichi Yamamoto, Akiko TJ Mechanical engineering and machinery In recent years there are growing interest in fabrication of bulk nanostructured metals and alloys by using severe plastic deformation (SPD) techniques as new alternative in producing bulk nanocrystalline materials. These techniques allows for processing of bulk, fully dense workpiece with ultrafine grains. Metal undergoes SPD processing in certain techniques such as high pressure torsion (HPT), equal-channel angular pressing (ECAP) or multi-directional forging (MDF) are subjected to extensive hydrostatic pressure that may be used to impart a very high strain to the bulk solid without the introduction of any significant change in overall dimension of the sample. The change in the structure (small grain size and high-volume fraction of grain boundaries) of the material may result in the corrosion behavior different from that of the coarse-grained material. Electrochemical measurements were done to understand the corrosion behavior of TiNi alloys before and after HPT deformation. The experiment was carried out using standard three electrode setup (a sample as working electrode; a platinum wire as a counter electrode and a saturated calomel electrode in saturated KCl as a reference electrode) with the surface area of 26.42 mm2 exposed to the EMEM+10% FBS cell culture medium. The measurements were performed in an incubator with controlled environment at 37 °C and 5% CO2, simulating the cell culture condition. The potential of the specimen was monitored over 1 hour, and the stabilized potential was used as the open-circuit potential (EOCP). Potentiodynamic curves were scanned in the potential range from −0.5 V to 1.5 V relative to the EOCP, at a rate of 0.5 mV/s. The result of OCP-time measurement done in the cell culture medium shows that the OCP of HPT-deformed samples shifts towards to the more positive rather than that of BHPT samples. The OCP of deformed samples were ennobled to more than +70 mV for Ti-50mol%. The shift of OCP towards the nobler direction indicates the passive nature of native oxides formed on the surface of the samples. The polarization curve, on the other hand, indicates that the HPT deformation was found to shift the passive current to nobler region. The passive region current density is found to be lower than that of the BHPT, suggesting the passive film formed on the surface of HPT-deformed samples is more protective than that of the BHPT sample. This study has shown that nanocrystallization and amorphization induced by severe plastic deformation change the corrosion behavior of TiNi alloys. AIP Publishing LLC. 2017-09 Conference or Workshop Item PeerReviewed pdf en http://umpir.ump.edu.my/id/eprint/20913/1/Corrosion%20behavior%20of%20HPT-deformed%20TiNi%20alloys.pdf Awang Shri, Dayangku Noorfazidah and Tsuchiya, Koichi and Yamamoto, Akiko (2017) Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium. In: 4th International Conference on the Advancement of Materials and Nanotechnology (ICAMN 2016), 9-11 November 2016 , Langkawi. pp. 1-6., 1877 (1). ISSN 0094243X ISBN 978-073541557-7 https://doi.org/10.1063/1.4999866
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Malaysia Pahang
building	UMP Institutional Repository
collection	Online Access
language	English
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery Awang Shri, Dayangku Noorfazidah Tsuchiya, Koichi Yamamoto, Akiko Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium
description	In recent years there are growing interest in fabrication of bulk nanostructured metals and alloys by using severe plastic deformation (SPD) techniques as new alternative in producing bulk nanocrystalline materials. These techniques allows for processing of bulk, fully dense workpiece with ultrafine grains. Metal undergoes SPD processing in certain techniques such as high pressure torsion (HPT), equal-channel angular pressing (ECAP) or multi-directional forging (MDF) are subjected to extensive hydrostatic pressure that may be used to impart a very high strain to the bulk solid without the introduction of any significant change in overall dimension of the sample. The change in the structure (small grain size and high-volume fraction of grain boundaries) of the material may result in the corrosion behavior different from that of the coarse-grained material. Electrochemical measurements were done to understand the corrosion behavior of TiNi alloys before and after HPT deformation. The experiment was carried out using standard three electrode setup (a sample as working electrode; a platinum wire as a counter electrode and a saturated calomel electrode in saturated KCl as a reference electrode) with the surface area of 26.42 mm2 exposed to the EMEM+10% FBS cell culture medium. The measurements were performed in an incubator with controlled environment at 37 °C and 5% CO2, simulating the cell culture condition. The potential of the specimen was monitored over 1 hour, and the stabilized potential was used as the open-circuit potential (EOCP). Potentiodynamic curves were scanned in the potential range from −0.5 V to 1.5 V relative to the EOCP, at a rate of 0.5 mV/s. The result of OCP-time measurement done in the cell culture medium shows that the OCP of HPT-deformed samples shifts towards to the more positive rather than that of BHPT samples. The OCP of deformed samples were ennobled to more than +70 mV for Ti-50mol%. The shift of OCP towards the nobler direction indicates the passive nature of native oxides formed on the surface of the samples. The polarization curve, on the other hand, indicates that the HPT deformation was found to shift the passive current to nobler region. The passive region current density is found to be lower than that of the BHPT, suggesting the passive film formed on the surface of HPT-deformed samples is more protective than that of the BHPT sample. This study has shown that nanocrystallization and amorphization induced by severe plastic deformation change the corrosion behavior of TiNi alloys.
format	Conference or Workshop Item
author	Awang Shri, Dayangku Noorfazidah Tsuchiya, Koichi Yamamoto, Akiko
author_facet	Awang Shri, Dayangku Noorfazidah Tsuchiya, Koichi Yamamoto, Akiko
author_sort	Awang Shri, Dayangku Noorfazidah
title	Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium
title_short	Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium
title_full	Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium
title_fullStr	Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium
title_full_unstemmed	Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium
title_sort	corrosion behavior of hpt-deformed tini alloys in cell culture medium
publisher	AIP Publishing LLC.
publishDate	2017
url	http://umpir.ump.edu.my/id/eprint/20913/ http://umpir.ump.edu.my/id/eprint/20913/ http://umpir.ump.edu.my/id/eprint/20913/1/Corrosion%20behavior%20of%20HPT-deformed%20TiNi%20alloys.pdf
first_indexed	2023-09-18T22:30:26Z
last_indexed	2023-09-18T22:30:26Z
_version_	1777416249522782208

Corrosion behavior of HPT-deformed TiNi alloys in cell culture medium

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