High Ductility in a fully martensitic microstructure: a paradox in a Ti alloy produced by selective laser melting. Issue 11 (2nd November 2018)

• Record Type: Journal Article
• Authors: Zafari, A.; Xia, K.
• Is Part Of: Materials research letters. Volume 6:Issue 11(2018)
• Page Start: 627
• Page End: 633
• Publication Date: 2018-11-02
• Subjects: Titanium alloys -- martensitic phase transformation -- ductility -- deformation structure -- selective laser melting; Materials science -- Research -- Periodicals; Biomedical materials -- Research -- Periodicals; Composite materials -- Research -- Periodicals; Biomedical materials -- Research; Composite materials -- Research; Materials science -- Research; Periodicals; 620.1105
• DOI: 10.1080/21663831.2018.1525773
• Languages: English
• ISSNs: 2166-3831

Abstract

ABSTRACT: A fully martensitic Ti alloy consisting entirely of hexagonal-close-packed α ′ was produced by selective laser melting (SLM), exhibiting an impressive combination of high strength and excellent ductility. A small quantity of body-centred-cubic β formed at some large primary α ′ plates oriented at ∼45° to the tensile direction was found responsible for early fracture owing to α ′/ β strain incompatibility. Properly selected SLM parameters resulted in a β -free microstructure containing α ′/ α ′ interfaces only, preventing premature fracture. Consequently, large plastic deformation was enabled, creating randomly oriented nano- α ′ crystals. The investigation dispels the myth that α ′ is inherently brittle. GRAPHICAL ABSTRACT: Impact Statement: A fully martensitic α ′ Ti-6Al-4V with an impressive combination of high ductility and strength was produced using selective laser melting, dispelling the myth that α ′ is inherently brittle.