{"paper_id":"b5a0c9b2-522c-4dcd-8d5a-0c41f69a5db5","body_text":"Influence of Post-Weld Heat Treatment on Mechanical Properties and Microstructure of Friction Stir Welded Rheocast AA6082 Joints | 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 Influence of Post-Weld Heat Treatment on Mechanical Properties and Microstructure of Friction Stir Welded Rheocast AA6082 Joints Worapong Boonchouytan, Kittima Sillapasa, Chaiyoot Meengam This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9085103/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 This study investigates the mechanical properties, microstructural changes, and fracture characteristics of friction stir welded (FSW) rheocast AA6082 aluminum alloy joints that underwent second-stage post-weld heat treatment (PWHT). All welds were executed utilizing optimal welding parameters of 910 rpm rotation speed and 113 mm/min welding speed to guarantee steady heat input and defect-free connections. Two post-weld heat treatment (PWHT) methods were assessed: artificial aging at 190°C for 6 to 18 hours and solution treatment at 550°C for 2 to 8 hours, succeeded by quenching and artificial aging. Microstructural analysis indicated that extended solution treatment increasingly destabilizes the dynamically recrystallized stir zone, resulting in grain coarsening and the emergence of micro-defects when the holding duration surpasses roughly 3 hours. Mechanical testing revealed that, whereas the base metal demonstrates a conventional strength–ductility trade-off, the welded joints undergo concurrent decreases in ultimate tensile strength from 251 MPa to 211 MPa and elongation from 3.89% to 2.80% as the period of solution treatment increases. As a result, joint efficiency diminishes from around 82% at 2 hours to 72% at 8 hours. Hardness tests reveal a rise in softening and heterogeneity inside the weld core with prolonged holding time. Fracture analysis indicated that ductile failure was mostly governed by microvoid coalescence under both ideal artificial aging (190°C for 12 hours) and solution treatment (550°C for 2 hours). A solution treatment at 550°C for 2 hours yields the optimal equilibrium among precipitation regulation, grain stability, hardness consistency, and joint efficacy. Friction stir welding Post-weld heat treatment Rheocast AA6082 Artificial aging Solution treatment Full Text Supplementary Files NoveltyandScientificContributionEdit.pdf 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9085103\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":605607627,\"identity\":\"71282748-701d-49a4-b82e-47bba85079b5\",\"order_by\":0,\"name\":\"Worapong Boonchouytan\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Ubon Ratchathani University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Worapong\",\"middleName\":\"\",\"lastName\":\"Boonchouytan\",\"suffix\":\"\"},{\"id\":605607628,\"identity\":\"f26e6d65-7561-439e-acd1-8389802f527d\",\"order_by\":1,\"name\":\"Kittima Sillapasa\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0ElEQVRIiWNgGAWjYBACCWYgkQBisTewQcV4CGlhZmwAa+E5ANXCRkgLA1ALhJVApBbJdv7jDx7m2DHIz3xj9piHwU6eQb73AF4t0iCHJW5LZjC4nWNuzMOQbNjAxpeAV4scRAszg4F0jpk0DwNzAtBhBsRoqQc67AxISz1hLVCHHWZguMED0nKYsBbJZmbDGYnbjvMYnEkrN5xjcNywjS0HvxaJ8wcffPy5rVpOvv3wtgdvKqrl+ZnP4NcCA9C4ACpmw69wFIyCUTAKRgExAABgITRVCmkAhAAAAABJRU5ErkJggg==\",\"orcid\":\"\",\"institution\":\"Ubon Ratchathani University\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Kittima\",\"middleName\":\"\",\"lastName\":\"Sillapasa\",\"suffix\":\"\"},{\"id\":605607629,\"identity\":\"aa202f31-c423-4a74-a7b8-11ea8cf9168f\",\"order_by\":2,\"name\":\"Chaiyoot Meengam\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Songkhla Rajabhat University\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Chaiyoot\",\"middleName\":\"\",\"lastName\":\"Meengam\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2026-03-10 14:21:18\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-9085103/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-9085103/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":108805341,\"identity\":\"cec43146-a3e9-4e2b-9b2c-6905cb5a136b\",\"added_by\":\"auto\",\"created_at\":\"2026-05-08 15:25:38\",\"extension\":\"pdf\",\"order_by\":1,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":2418489,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"WeldWorldworapongEdit.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9085103/v1_covered_cad3450b-37c6-4241-96ac-7fbfbd922057.pdf\"},{\"id\":104684004,\"identity\":\"feb1ac53-1575-427b-9b92-8c35a7c5580e\",\"added_by\":\"auto\",\"created_at\":\"2026-03-16 03:44:44\",\"extension\":\"pdf\",\"order_by\":4,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":113895,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"NoveltyandScientificContributionEdit.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-9085103/v1/366b6a08d05b31b378b30f2b.pdf\"}],\"financialInterests\":\"\",\"formattedTitle\":\"Influence of Post-Weld Heat Treatment on Mechanical Properties and Microstructure of Friction Stir Welded Rheocast AA6082 Joints\",\"fulltext\":[],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":false,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":true,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":true,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":true,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"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\":\"Friction stir welding, Post-weld heat treatment, Rheocast AA6082, Artificial aging, Solution treatment\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-9085103/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-9085103/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eThis study investigates the mechanical properties, microstructural changes, and fracture characteristics of friction stir welded (FSW) rheocast AA6082 aluminum alloy joints that underwent second-stage post-weld heat treatment (PWHT). All welds were executed utilizing optimal welding parameters of 910 rpm rotation speed and 113 mm/min welding speed to guarantee steady heat input and defect-free connections. Two post-weld heat treatment (PWHT) methods were assessed: artificial aging at 190\\u0026deg;C for 6 to 18 hours and solution treatment at 550\\u0026deg;C for 2 to 8 hours, succeeded by quenching and artificial aging. Microstructural analysis indicated that extended solution treatment increasingly destabilizes the dynamically recrystallized stir zone, resulting in grain coarsening and the emergence of micro-defects when the holding duration surpasses roughly 3 hours. Mechanical testing revealed that, whereas the base metal demonstrates a conventional strength\\u0026ndash;ductility trade-off, the welded joints undergo concurrent decreases in ultimate tensile strength from 251 MPa to 211 MPa and elongation from 3.89% to 2.80% as the period of solution treatment increases. As a result, joint efficiency diminishes from around 82% at 2 hours to 72% at 8 hours. Hardness tests reveal a rise in softening and heterogeneity inside the weld core with prolonged holding time. Fracture analysis indicated that ductile failure was mostly governed by microvoid coalescence under both ideal artificial aging (190\\u0026deg;C for 12 hours) and solution treatment (550\\u0026deg;C for 2 hours). A solution treatment at 550\\u0026deg;C for 2 hours yields the optimal equilibrium among precipitation regulation, grain stability, hardness consistency, and joint efficacy.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Influence of Post-Weld Heat Treatment on Mechanical Properties and Microstructure of Friction Stir Welded Rheocast AA6082 Joints\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2026-03-16 03:44:40\",\"doi\":\"10.21203/rs.3.rs-9085103/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"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}}],\"origin\":\"\",\"ownerIdentity\":\"9bfa8f32-5393-4ea7-8701-d2f23586b2b5\",\"owner\":[],\"postedDate\":\"March 16th, 2026\",\"published\":true,\"recentEditorialEvents\":[{\"type\":\"decision\",\"content\":\"Reject, do not transfer\",\"date\":\"2026-05-06T01:40:32+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"posted\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2026-05-06T05:41:21+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2026-03-16 03:44:40\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-9085103\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-9085103\",\"identity\":\"rs-9085103\",\"version\":[\"v1\"]},\"buildId\":\"XKTyCvWXoU3ODBz1xrDgd\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}