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Evaluation of structure and mechanical properties of Ni-rich NiTi/Kapton composite film

Mohri, Maryam and Nili-Ahmadabadi, Mahmoud and PouryazdanPanah, Mohsen and Hahn, Horst (2016):
Evaluation of structure and mechanical properties of Ni-rich NiTi/Kapton composite film.
In: Materials Science and Engineering: A, Elsevier Science SA, Switzerland, pp. 13-19, 668, ISSN 09215093,
[Online-Edition: https://doi.org/10.1016/j.msea.2016.05.044],
[Article]

Abstract

NiTi thin films are usually sputtered on silicon wafers by magnetron sputtering. But the systems composed of thin film on flexible polymeric substrate are used in many applications such as micro electromechanical systems (MEMS). Investigation on mechanical properties of thin films has attracted much attention due to their widespread applications. In this paper, the mechanical properties of 1 mu m-thick crystallized Ni-49.2 at%Ti thin film alloy deposited by DC magnetron sputtering on Kapton substrate are investigated by using tensile test. The as-deposited thin films are in amorphous state, then for crystallization, the thin film was annealed at 450 degrees C for 30 min. Formation of the austenite phase after annealing was confirmed by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The surface morphology of as deposited and crystallized thin films were examined by scanning electron microscopy (SEM). Stress-strain curves of the NiTi alloy thin film were obtained by subtracting of the stress-strain Kapton curves from the corresponding curves of the NiTi/Kapton composite. The XRD results revealed that the NiTi thin film deposited on the Kapton is austenitic and presents super-elastic effect at room temperature. This pseudo elastic effect leads to more recoverable strain in NiTi/Kapton composite film compared with Kapton foils on loading/unloading test. Furthermore, it was concluded that nanostructure of the NiTi thin film is responsible for remarkable improvement of ultimate tensile strength (1.4 GPa) at a strain of 30% compared with the bulk material. (C) 2016 Elsevier B.V. All rights reserved.

Item Type: Article
Erschienen: 2016
Creators: Mohri, Maryam and Nili-Ahmadabadi, Mahmoud and PouryazdanPanah, Mohsen and Hahn, Horst
Title: Evaluation of structure and mechanical properties of Ni-rich NiTi/Kapton composite film
Language: English
Abstract:

NiTi thin films are usually sputtered on silicon wafers by magnetron sputtering. But the systems composed of thin film on flexible polymeric substrate are used in many applications such as micro electromechanical systems (MEMS). Investigation on mechanical properties of thin films has attracted much attention due to their widespread applications. In this paper, the mechanical properties of 1 mu m-thick crystallized Ni-49.2 at%Ti thin film alloy deposited by DC magnetron sputtering on Kapton substrate are investigated by using tensile test. The as-deposited thin films are in amorphous state, then for crystallization, the thin film was annealed at 450 degrees C for 30 min. Formation of the austenite phase after annealing was confirmed by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The surface morphology of as deposited and crystallized thin films were examined by scanning electron microscopy (SEM). Stress-strain curves of the NiTi alloy thin film were obtained by subtracting of the stress-strain Kapton curves from the corresponding curves of the NiTi/Kapton composite. The XRD results revealed that the NiTi thin film deposited on the Kapton is austenitic and presents super-elastic effect at room temperature. This pseudo elastic effect leads to more recoverable strain in NiTi/Kapton composite film compared with Kapton foils on loading/unloading test. Furthermore, it was concluded that nanostructure of the NiTi thin film is responsible for remarkable improvement of ultimate tensile strength (1.4 GPa) at a strain of 30% compared with the bulk material. (C) 2016 Elsevier B.V. All rights reserved.

Journal or Publication Title: Materials Science and Engineering: A
Volume: 668
Publisher: Elsevier Science SA, Switzerland
Uncontrolled Keywords: NiTi/Kapton Composite, Thin film, Pseudo elastic effect, Tensile test
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Joint Research Laboratory Nanomaterials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 26 Jul 2017 09:29
Official URL: https://doi.org/10.1016/j.msea.2016.05.044
Identification Number: doi:10.1016/j.msea.2016.05.044
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