A Study on NiTiSn Low-Temperature Shape Memory Alloys and the Processing of NiTiHf High-Temperature Shape Memory Alloys Metadata
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Title
- Main Title A Study on NiTiSn Low-Temperature Shape Memory Alloys and the Processing of NiTiHf High-Temperature Shape Memory Alloys
Creator
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Author: Young, Avery WCreator Type: Personal
Contributor
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Chair: Young, Marcus L.Contributor Type: PersonalContributor Info: Major Professor
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Committee Member: Benafan, OthmaneContributor Type: Personal
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Committee Member: Mukherjee, SundeepContributor Type: Personal
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Committee Member: Du, JinchengContributor Type: Personal
Publisher
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Name: University of North TexasPlace of Publication: Denton, TexasAdditional Info: www.unt.edu
Date
- Creation: 2018-05
Language
- English
Description
- Content Description: Shape memory alloys (SMAs) operating as solid-state actuators pose economic and environmental benefits to the aerospace industry due to their lightweight, compact design, which provides potential for reducing fuel emissions and overall operating cost in aeronautical equipment. Despite wide applicability, the implementation of SMA technology into aerospace-related actuator applications is hindered by harsh environmental conditions, which necessitate extremely high or low transformation temperatures. The versatility of the NiTi-based SMA system shows potential for meeting these demanding material constraints, since transformation temperatures in NiTi can be significantly raised or lowered with ternary alloying elements and/or Ni:Ti ratio adjustments. In this thesis, the expansive transformation capabilities of the NiTi-based SMA system are demonstrated with a low and high-temperature NiTi-based SMA; each encompassing different stages of the SMA development process. First, exploratory work on the NiTiSn SMA system is presented. The viability of NiTiSn alloys as low-temperature SMAs (LTSMAs) was investigated over the course of five alloy heats. The site preference of Sn in near-equiatomic NiTi was examined along with the effects of solution annealing, Ni:Ti ratio adjustments, and precipitation strengthening on the thermomechanical properties of NiTiSn LTSMAs. Second, the thermomechanical processability of NiTiHf high-temperature SMA (HTSMA) wires is presented. The evolution of various microstructural features (grain size reduction, oxide growth, and nano-precipitation) were observed at incremental stages of the hot rolling process and linked to the thermal and mechanical responses of respective HTSMA rods/wires. This work was carried out in an effort to optimize the rolling/drawing process for NiTiHf HTSMAs.
- Physical Description: viii, 68 pages
Subject
- Keyword: shape
- Keyword: memory
- Keyword: alloys
- Keyword: Ni
- Keyword: Ti
- Keyword: Hf
- Keyword: Sn
- Keyword: SMA
- Keyword: low temperature
- Keyword: high temperature
- Keyword: metallurgy
- Keyword: aerospace
- Keyword: actuator
- Keyword: processing
- Keyword: alloy
- Keyword: design
- Keyword: microstructure
- Keyword: grain size
- Keyword: transformation
- Keyword: austenite
- Keyword: martensite
- Keyword: phase transformation
- Keyword: Engineering, Materials Science
- Library of Congress Subject Headings: Shape memory alloys -- Effect of temperature on.
- Library of Congress Subject Headings: Nickel-titanium alloys -- Effect of temperature on.
Collection
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Name: UNT Theses and DissertationsCode: UNTETD
Institution
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Name: UNT LibrariesCode: UNT
Rights
- Rights Access: public
- Rights Holder: Young, Avery W
- Rights License: copyright
- Rights Statement: Copyright is held by the author, unless otherwise noted. All rights Reserved.
Resource Type
- Thesis or Dissertation
Format
- Text
Identifier
- Accession or Local Control No: submission_1143
- Archival Resource Key: ark:/67531/metadc1157642
Degree
- Degree Name: Master of Science
- Degree Level: Master's
- Academic Department: Department of Materials Science and Engineering
- College: College of Engineering
- Degree Discipline: Materials Science and Engineering
- Degree Publication Type: thesi
- Degree Grantor: University of North Texas
Note
- Embargo Note: The work will be published after approval.