Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi Alloy

In the current paper, a predefined thermomechanical procedure has been applied to the two-way shape memory effect (TWSME) in a NiTi alloy to study the effect of two different applied load conditions on the induced martensitic state. The microstructure of the strips was studied using optical microsco...

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Main Authors: Ali Tahaei, Ali Aghajani, Mahmoud Abbasi, Behrouz Bagheri, Mattia Merlin, Gian Luca Garagnani
Format: Article
Language:English
Published: Wiley 2023-01-01
Series:Advances in Materials Science and Engineering
Online Access:http://dx.doi.org/10.1155/2023/1524836
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author Ali Tahaei
Ali Aghajani
Mahmoud Abbasi
Behrouz Bagheri
Mattia Merlin
Gian Luca Garagnani
author_facet Ali Tahaei
Ali Aghajani
Mahmoud Abbasi
Behrouz Bagheri
Mattia Merlin
Gian Luca Garagnani
author_sort Ali Tahaei
collection DOAJ
description In the current paper, a predefined thermomechanical procedure has been applied to the two-way shape memory effect (TWSME) in a NiTi alloy to study the effect of two different applied load conditions on the induced martensitic state. The microstructure of the strips was studied using optical microscopy (OM), scanning electron microscopy (SEM) fitted with an EDS microprobe, and microhardness tests at the end of both the training and thermal cycles. Inducing internal stresses along specified directions during training cycles results in the formation of oriented martensitic variants rather than expected twinned martensitic variants upon cooling. It was found that the microstructure is made up of interlocking martensitic lathes, including the fine martensite colony next to the coarse martensite lathes. Furthermore, the results of the average hardness tests for bending at one point and three points were 241 and 247 HV0.2, respectively. It was shown that only the cubic austenitic phase (B2) and the martensitic monoclinic phase (B19′) experience transformation. The results reveal that homogeneous bending in three locations leads to achieving the best difference between high- and low-temperature curvatures after training.
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publishDate 2023-01-01
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series Advances in Materials Science and Engineering
spelling doaj-art-4cffabbdfcb047f2a22c1d61dccd2d1b2025-08-20T02:17:40ZengWileyAdvances in Materials Science and Engineering1687-84422023-01-01202310.1155/2023/1524836Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi AlloyAli Tahaei0Ali Aghajani1Mahmoud Abbasi2Behrouz Bagheri3Mattia Merlin4Gian Luca Garagnani5Kharazmi UniversityKharazmi UniversityAmirkabir University of TechnologyAmirkabir University of TechnologyUniversity of FerraraUniversity of FerraraIn the current paper, a predefined thermomechanical procedure has been applied to the two-way shape memory effect (TWSME) in a NiTi alloy to study the effect of two different applied load conditions on the induced martensitic state. The microstructure of the strips was studied using optical microscopy (OM), scanning electron microscopy (SEM) fitted with an EDS microprobe, and microhardness tests at the end of both the training and thermal cycles. Inducing internal stresses along specified directions during training cycles results in the formation of oriented martensitic variants rather than expected twinned martensitic variants upon cooling. It was found that the microstructure is made up of interlocking martensitic lathes, including the fine martensite colony next to the coarse martensite lathes. Furthermore, the results of the average hardness tests for bending at one point and three points were 241 and 247 HV0.2, respectively. It was shown that only the cubic austenitic phase (B2) and the martensitic monoclinic phase (B19′) experience transformation. The results reveal that homogeneous bending in three locations leads to achieving the best difference between high- and low-temperature curvatures after training.http://dx.doi.org/10.1155/2023/1524836
spellingShingle Ali Tahaei
Ali Aghajani
Mahmoud Abbasi
Behrouz Bagheri
Mattia Merlin
Gian Luca Garagnani
Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi Alloy
Advances in Materials Science and Engineering
title Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi Alloy
title_full Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi Alloy
title_fullStr Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi Alloy
title_full_unstemmed Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi Alloy
title_short Effects of Predefined Thermomechanical Procedure on the Microstructure and Mechanical Properties of the Two-Way Shape Memory Effect in the NiTi Alloy
title_sort effects of predefined thermomechanical procedure on the microstructure and mechanical properties of the two way shape memory effect in the niti alloy
url http://dx.doi.org/10.1155/2023/1524836
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