{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,2]],"date-time":"2026-11-02T23:07:49Z","timestamp":1793660869428,"version":"4.5.1"},"reference-count":35,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2025,9,2]],"date-time":"2025-09-02T00:00:00Z","timestamp":1756771200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"China Postdoctoral Science Foundation","award":["2020M672016"],"award-info":[{"award-number":["2020M672016"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>The reduced ductility caused by the brittle needle-like \u03b1\u2032 martensite limits the application of TC4 alloys produced by selective laser melting (SLM). Appropriate heat treatment can improve the microstructures and properties of SLM-fabricated TC4 alloys. In this work, SLM-fabricated TC4 alloys underwent stress relief annealing at 600 \u00b0C and high-temperature annealing at 800 \u00b0C. The effects of heat treatment temperature on phase composition, microstructural morphology, grain orientation, and mechanical properties were investigated. Meanwhile, the microstructural evolution and fracture mechanisms during the heat treatment process were analyzed. The results indicate that after annealing at 600 \u00b0C, the needle-like \u03b1\u2032 phase transforms into elongated \u03b1, and nano-\u03b2 phase increases. When annealed at 800 \u00b0C, the \u03b1\u2032 phase completely transforms into a more stable lath-shaped \u03b1 phase and a short rod-shaped \u03b2 phase, with the nano-\u03b2 phase disappearing. The texture orientation gradually shifts from &lt;0001&gt; towards &lt;01-10&gt;, where slip systems are more active. Additionally, heat treatment promotes the transition of grain boundaries to high-angle grain boundaries, thereby alleviating stress concentration and enhancing solid-solution strengthening. After heat treatment, the ultimate tensile strength of the material slightly decreases, but the elongation significantly increases. As the annealing temperature increased, the elongation (EL) improved from 5.22% to 11.43%. Following high-temperature annealing at 800 \u00b0C, necking and larger dimples appear on the fracture surface, and the fracture mechanism shifts from a mixed brittle\u2013ductile fracture to a ductile fracture. This work provides a theoretical basis for improving the microstructures and properties of SLM-fabricated TC4 alloys through heat treatment.<\/jats:p>","DOI":"10.3390\/ma18174126","type":"journal-article","created":{"date-parts":[[2025,9,2]],"date-time":"2025-09-02T14:16:55Z","timestamp":1756822615000},"page":"4126","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Effect of Heat Treatment on Microstructures and Mechanical Properties of TC4 Alloys Prepared by Selective Laser Melting"],"prefix":"10.3390","volume":"18","author":[{"given":"Jian","family":"Zhang","sequence":"first","affiliation":[{"name":"College of Mechanical & Electrical Engineering, Jining University, Jining 273155, China"},{"name":"College of Mechanical & Electrical Engineering, Wenzhou University, Wenzhou 325006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuhuan","family":"Shi","sequence":"additional","affiliation":[{"name":"College of Mechanical & Electrical Engineering, Wenzhou University, Wenzhou 325006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Su","family":"Shen","sequence":"additional","affiliation":[{"name":"College of Mechanical & Electrical Engineering, Jining University, Jining 273155, China"},{"name":"College of Mechanical & Electrical Engineering, Wenzhou University, Wenzhou 325006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0428-9433","authenticated-orcid":false,"given":"Shengdong","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Mechanical & Electrical Engineering, Jining University, Jining 273155, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Honghui","family":"Ding","sequence":"additional","affiliation":[{"name":"College of Mechanical & Electrical Engineering, Wenzhou University, Wenzhou 325006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1104-0908","authenticated-orcid":false,"given":"Xiaoming","family":"Pan","sequence":"additional","affiliation":[{"name":"College of Mechanical & Electrical Engineering, Wenzhou University, Wenzhou 325006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.actamat.2015.06.036","article-title":"Graded microstructure and mechanical properties of additive manufactured Ti-6Al-4V via electron beam melting","volume":"97","author":"Tan","year":"2015","journal-title":"Acta Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3303","DOI":"10.1016\/j.actamat.2010.02.004","article-title":"A study of the microstructural evolution during selective laser melting of Ti\u20136Al\u20134V","volume":"58","author":"Thijs","year":"2010","journal-title":"Acta Mater."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"410","DOI":"10.1016\/j.matdes.2016.11.092","article-title":"The design and manufacturing of a titanium alloy beak for Grus japonensis using additive manufacturing","volume":"117","author":"Song","year":"2017","journal-title":"Mater. 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