Martensitic transformations in Ti-6Al-4V (ELI) alloy manufactured by 3D Printing
- Karlstad University, SE-651 88 Karlstad (Sweden)
- Chalmers University of Technology, Department of Physics, Göteborg SE-412 96 (Sweden)
- Central University of Technology, Free State, Department of Mechanical and Mechatronic Engineering, Private Bag X20539, Bloemfontein 9300 (South Africa)
- Institute of Metal Physics, 620990 Ekaterinburg, 18, S. Kovalevskaya Str. (Russian Federation)
Highlights: • Two metastable martensitic phases, namely α′′ and α′ may be formed in Ti-6Al-4V during 3D manufacturing process. In the present investigation, Ti-6Al-4V ELI samples were manufactured by the powder-bed fusion (PBF) process using the laser sintering (LS) technology. Microstructure, chemical and phase constitution, and mechanical properties were studied by means of the transmission electron microscopy, atom probe tomography, X-ray diffraction, nanoindentation and mechanical testing. It was found that the structure of LS samples consisted of two different variants of metastable phases, namely the hexagonal α′ martensitic phase and small amounts of the orthorhombic α″ martensitic phase. The martensitic α′-phase was formed because of the high cooling rates of the LS method. The {10 1-bar 2} 1-bar 011 hexagonal martensite tensile twins were observed in the microstructure of the as-build alloy. Small areas with inner twinning martensitic plates, which are typical for the metastable orthorhombic martensitic phase in titanium alloys, were identified by the transmission electron microscopy. Atom probe tomography (APT) confirmed localization of β-stabilizing elements at interfaces, presumably at the twin or lamella boundaries. The structure and origin of the martensitic phases in 3D printed Ti-6Al-4V alloys are discussed with respect to in-situ heat treatment during manufacturing.
- OSTI ID:
- 23112947
- Journal Information:
- Materials Characterization, Vol. 146; Other Information: Published by Elsevier Inc.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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