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Oxidation induced mechanisms during directed energy deposition additive manufactured titanium alloy builds

DOI: 10.1016/j.addlet.2021.100022 DOI Help

Authors: Caterina Iantaffi (University College London; Research Complex at Harwell) , Chu Lun Alex Leung (University College London; Research Complex at Harwell) , Yunhui Chen (University College London; Research Complex at Harwell) , Shaoliang Guan (Cardiff University; HarwellXPS, Research Complex at Harwell) , Robert C. Atwood (Diamond Light Source) , Jedsada Lertthanasarn (Imperial College London) , Minh-Son Pham (Imperial College London) , Martina Meisnar (ESA-RAL Advanced Manufacturing Laboratory) , Thomas Rohr (European Space Agency, ESTEC) , Peter D. Lee (University College London; Research Complex at Harwell)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Additive Manufacturing Letters , VOL 143

State: Published (Approved)
Published: November 2021
Diamond Proposal Number(s): 20096

Open Access Open Access

Abstract: To prevent oxygen contamination, additive manufacturing (AM) techniques normally operate in an inert gas chamber (GC). An alternative method, useful for large builds and components repair, is the application of localised shielding gas (LSG). The effect of oxygen contamination on Ti6242 during directed energy deposition (DED) AM using an inert GC compared to LSG was investigated by in situ synchrotron X-ray experiments. When processing in LSG mode, the amount of oxygen absorbed from the atmosphere was sufficient to reverse the Marangoni flow leading to an alteration of the molten pool geometry and strongly influencing defect formation. Microstructural analysis reveals that, at high oxygen levels, the commonly developed α' martensitic microstructure was completely suppressed, forming precipitation of a tetra modal microstructure of α phase consisting of globular, primary and secondary lamellae (in colonies) and basketweave structure. These results help elucidate the influence of oxygen contamination in additively manufactured Ti alloys, potentially enabling improved industrial practices for AM of titanium alloy.

Journal Keywords: titanium alloys; oxidation; laser additive manufacturing; directed-energy deposition

Diamond Keywords: Alloys; Additive Manufacturing

Subject Areas: Materials, Engineering

Instruments: I12-JEEP: Joint Engineering, Environmental and Processing

Added On: 24/11/2021 10:50


Discipline Tags:

Materials Engineering & Processes Materials Science Engineering & Technology Metallurgy

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Imaging Tomography