Monoclinic Angle of the B19′ Phase in a Cold Worked NiTi

Yingchao Li; Sam Bakhtiari; Dawn Xu; Hong Yang; Yinong Liu

doi:10.1007/s40830-025-00521-4

Monoclinic Angle of the B19′ Phase in a Cold Worked NiTi

Yingchao Li
, Sam Bakhtiari
, Dawn Xu
, Hong Yang
, Yinong Liu

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

This study evaluated the monoclinic angle of the B19′ martensite in a cold worked equiatomic Ni₅₀Ti₅₀ alloy by means of transmission electron microscopy (TEM) analysis. It also presents a minimum error approach to determining the small changes to the monoclinic angle based on Fast Fourier Transformation patterns generated from high resolution TEM micrographs. The monoclinic angle of the B19′ martensite was found to reduce from 97.3° in the annealed state to 93.8° after 24.4% cold deformation by wire drawing. Such finding may help to interpret some common experimental observations such as the reduction of transformation strains in cold worked NiTi shape memory alloys or in alloys after thermal transformation cycling.

Original language	English
Article number	015031
Pages (from-to)	176-182
Number of pages	7
Journal	Shape Memory and Superelasticity
Volume	11
Issue number	2
Early online date	14 Feb 2025
DOIs	https://doi.org/10.1007/s40830-025-00521-4
Publication status	Published - Jun 2025

Funding

Funders	Funder number
ARC Australian Research Council	DP190102990

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10.1007/s40830-025-00521-4Licence: CC BY

Cite this

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title = "Monoclinic Angle of the B19′ Phase in a Cold Worked NiTi",

abstract = "This study evaluated the monoclinic angle of the B19′ martensite in a cold worked equiatomic Ni50Ti50 alloy by means of transmission electron microscopy (TEM) analysis. It also presents a minimum error approach to determining the small changes to the monoclinic angle based on Fast Fourier Transformation patterns generated from high resolution TEM micrographs. The monoclinic angle of the B19′ martensite was found to reduce from 97.3° in the annealed state to 93.8° after 24.4\% cold deformation by wire drawing. Such finding may help to interpret some common experimental observations such as the reduction of transformation strains in cold worked NiTi shape memory alloys or in alloys after thermal transformation cycling.",

keywords = "Martensite, Monoclinic angle, NiTi, Shape memory alloys, Transmission electron microscopy",

author = "Yingchao Li and Sam Bakhtiari and Dawn Xu and Hong Yang and Yinong Liu",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2025.",

year = "2025",

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doi = "10.1007/s40830-025-00521-4",

language = "English",

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T1 - Monoclinic Angle of the B19′ Phase in a Cold Worked NiTi

AU - Li, Yingchao

AU - Bakhtiari, Sam

AU - Xu, Dawn

AU - Yang, Hong

AU - Liu, Yinong

N1 - Publisher Copyright: © The Author(s) 2025.

PY - 2025/6

Y1 - 2025/6

N2 - This study evaluated the monoclinic angle of the B19′ martensite in a cold worked equiatomic Ni50Ti50 alloy by means of transmission electron microscopy (TEM) analysis. It also presents a minimum error approach to determining the small changes to the monoclinic angle based on Fast Fourier Transformation patterns generated from high resolution TEM micrographs. The monoclinic angle of the B19′ martensite was found to reduce from 97.3° in the annealed state to 93.8° after 24.4% cold deformation by wire drawing. Such finding may help to interpret some common experimental observations such as the reduction of transformation strains in cold worked NiTi shape memory alloys or in alloys after thermal transformation cycling.

AB - This study evaluated the monoclinic angle of the B19′ martensite in a cold worked equiatomic Ni50Ti50 alloy by means of transmission electron microscopy (TEM) analysis. It also presents a minimum error approach to determining the small changes to the monoclinic angle based on Fast Fourier Transformation patterns generated from high resolution TEM micrographs. The monoclinic angle of the B19′ martensite was found to reduce from 97.3° in the annealed state to 93.8° after 24.4% cold deformation by wire drawing. Such finding may help to interpret some common experimental observations such as the reduction of transformation strains in cold worked NiTi shape memory alloys or in alloys after thermal transformation cycling.

KW - Martensite

KW - Monoclinic angle

KW - NiTi

KW - Shape memory alloys

KW - Transmission electron microscopy

UR - https://www.scopus.com/pages/publications/85217741309

U2 - 10.1007/s40830-025-00521-4

DO - 10.1007/s40830-025-00521-4

M3 - Article

AN - SCOPUS:85217741309

SN - 2199-384X

VL - 11

SP - 176

EP - 182

JO - Shape Memory and Superelasticity

JF - Shape Memory and Superelasticity

IS - 2

M1 - 015031

ER -

Monoclinic Angle of the B19′ Phase in a Cold Worked NiTi

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Approaching near-ideal strength for bulk amorphous metals

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Monoclinic Angle of the B19′ Phase in a Cold Worked NiTi

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Approaching near-ideal strength for bulk amorphous metals

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