Impact of Short-Term Annealing on Microstructure and Transformation Temperatures of Hot-Rolled Superelastic Nitinol

Impact of Short-Term Annealing on Microstructure and Transformation Temperatures of Hot-Rolled Superelastic Nitinol | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Impact of Short-Term Annealing on Microstructure and Transformation Temperatures of Hot-Rolled Superelastic Nitinol Seyed Aref Golsorkhi, Melodie Fickenscher, Le Zhou, Dinc Erdeniz This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8149363/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Brief heat treatments offer an energy-efficient method for adjusting the microstructure and properties of Nitinol; yet, the microstructural mechanisms occurring during early stages of these treatments remain largely unrecorded. In this study, a hot-rolled superelastic sheet was annealed for 60 seconds at temperatures of 520, 540, 560, 580, and 600 ºC. After annealing, the samples were analyzed using transmission electron microscopy, electron backscatter diffraction, X-ray diffraction, and differential scanning calorimetry. After a 1-minute heat treatment at 520–600 ºC, the dislocation density drops by three orders of magnitude. The texture shifts from a rolling α-fiber ( || RD) to a recrystallized, γ-rich state ({111} || ND) with increasing {001}. At 520 ºC, the change is mostly recovery; by 560 ºC, oriented recrystallization near {111} dominates; at 580–600 ºC, growth/coarsening broadens the γ fiber and partially de-textures the sheet. Simultaneously, defect-assisted precipitation of coherent Ni 4 Ti 3 plates preserved the recovered texture and stabilized a multi-step transformation. Quantitative correlations among recovery, texture retention, and nanoscale precipitation were established, demonstrating that a one-minute treatment at moderate temperatures can achieve fine grains and minimal defect content. The study offers a commercially viable method for the rapid and customizable post-processing of NiTi components. Nickel-Titanium (Nitinol) Superelasticity Phase Transformations Annealing Precipitation Recovery Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8149363","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":547183594,"identity":"ccfb2766-c8b2-45fe-b819-ea1fcba79219","order_by":0,"name":"Seyed Aref Golsorkhi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA30lEQVRIiWNgGAWjYBAC/gbmBjDNDyQOPIAIGuDVInGAEaxFciaQOpBAjBYDBqiWDQeAJHFa2BubP3zcUydhfO3wQ6Ath+UZ2Ju3SeDVwnOwTXLGs8MSZrfTDEBaDBt4jpXh1WJ4I7GNmefAgTqz2wlgLQkMEjlm+G25kdj8mecA0GGz0z9AtMi/IailQZrnALOEgXQOzBYe/FokzoD8cuCwhMTtnIIDCQbphm08acUW+LTwtzcf/vAB6DD+2embP3yosJbnZz+88QY+LejuZGBgI0H5KBgFo2AUjAIcAAAH00zYutPkswAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0009-0002-8485-1402","institution":"University of Cincinnati","correspondingAuthor":true,"prefix":"","firstName":"Seyed","middleName":"Aref","lastName":"Golsorkhi","suffix":""},{"id":547183639,"identity":"5efe53c0-cba4-47f9-ba9e-2015360712f1","order_by":1,"name":"Melodie Fickenscher","email":"","orcid":"","institution":"University of Cincinnati","correspondingAuthor":false,"prefix":"","firstName":"Melodie","middleName":"","lastName":"Fickenscher","suffix":""},{"id":547183640,"identity":"31d8b0f9-d974-4d59-a7af-1e9dc07a2983","order_by":2,"name":"Le Zhou","email":"","orcid":"","institution":"Marquette University","correspondingAuthor":false,"prefix":"","firstName":"Le","middleName":"","lastName":"Zhou","suffix":""},{"id":547183641,"identity":"f3ee2037-6857-438b-a710-fb21abffd68a","order_by":3,"name":"Dinc Erdeniz","email":"","orcid":"","institution":"University of Cincinnati","correspondingAuthor":false,"prefix":"","firstName":"Dinc","middleName":"","lastName":"Erdeniz","suffix":""}],"badges":[],"createdAt":"2025-11-18 23:22:22","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-8149363/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8149363/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":96453851,"identity":"8206ba59-78e3-4755-8929-c6791532a948","added_by":"auto","created_at":"2025-11-21 10:01:53","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1181743,"visible":true,"origin":"","legend":"","description":"","filename":"ShortTermAnnealingofSuperelasticNitinolvsub.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8149363/v1_covered_a1dcd3e4-5d05-406d-a5e1-d4e65f2a156a.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eImpact of Short-Term Annealing on Microstructure and Transformation Temperatures of Hot-Rolled Superelastic Nitinol\u003c/strong\u003e\u003c/p\u003e","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"University of Cincinnati","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Nickel-Titanium (Nitinol), Superelasticity, Phase Transformations, Annealing, Precipitation, Recovery","lastPublishedDoi":"10.21203/rs.3.rs-8149363/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8149363/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBrief heat treatments offer an energy-efficient method for adjusting the microstructure and properties of Nitinol; yet, the microstructural mechanisms occurring during early stages of these treatments remain largely unrecorded. In this study, a hot-rolled superelastic sheet was annealed for 60 seconds at temperatures of 520, 540, 560, 580, and 600 ºC. After annealing, the samples were analyzed using transmission electron microscopy, electron backscatter diffraction, X-ray diffraction, and differential scanning calorimetry. After a 1-minute heat treatment at 520–600 ºC, the dislocation density drops by three orders of magnitude. The texture shifts from a rolling α-fiber (\u0026lt;110\u0026gt; || RD) to a recrystallized, γ-rich state ({111} || ND) with increasing {001}. At 520 ºC, the change is mostly recovery; by 560 ºC, oriented recrystallization near {111} \u0026lt;112\u0026gt; dominates; at 580–600 ºC, growth/coarsening broadens the γ fiber and partially de-textures the sheet. Simultaneously, defect-assisted precipitation of coherent Ni\u003csub\u003e4\u003c/sub\u003eTi\u003csub\u003e3\u003c/sub\u003e plates preserved the recovered texture and stabilized a multi-step transformation. Quantitative correlations among recovery, texture retention, and nanoscale precipitation were established, demonstrating that a one-minute treatment at moderate temperatures can achieve fine grains and minimal defect content. 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