Electron backscatter diffraction characterization of fatigue crack growth in laser metal wire deposited Ti-6Al-4V

Journal Article · Mon Jan 15 00:00:00 EST 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2017.11.041· OSTI ID:22804865

Pia, Akerfeldt ^[1]; Colliander, Magnus Hörnqvist ^[2]; Pederson, Robert ^[1]; Antti, Marta-Lena ^[1]

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1. Division of Materials Science, Luleå University of Technology, S-97187 Luleå (Sweden)
2. Department of Physics, Chalmers University of Technology, S-41296 Göteborg (Sweden)

Highlights: • No difference in fatigue crack growth rate was confirmed within the material. • The tortuosity of the crack propagation could be related to the alpha colonies. • Large areas with similar crystallographic orientation were observed. - Abstract: By additive manufacturing (AM) there is a feasibility of producing near net shape components in basically one step from 3D CAD model to final product. The interest for AM is high and during the past decade a lot of research has been carried out in order to understand the influence from process parameters on the microstructure and furthermore on the mechanical properties. In the present study laser metal wire deposition of Ti-6Al-4V has been studied in detail with regard to its fatigue crack propagation characteristics. Two specimen orientations, parallel and perpendicular to the deposition direction, have been evaluated at room temperature and at 250 °C. No difference in the fatigue crack growth rate could be confirmed for the two specimen orientations. However, in the fractographic study it was observed that the tortuosity varied between certain regions on the fracture surface. The local crack path characteristic could be related to the alpha colony size and/or the crystallographic orientation. Moreover, large areas exhibiting similar crystallographic orientation were observed along the prior beta grain boundaries, which were attributed to the wide alpha colonies frequently observed along the prior beta grain boundaries.

• OSTI ID: 22804865
• Journal Information: Materials Characterization, Vol. 135; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADDITIVES
ALUMINIUM COMPOUNDS
BACKSCATTERING
CRACK PROPAGATION
CRYSTALLOGRAPHY
DEPOSITION
ELECTRON DIFFRACTION
GRAIN BOUNDARIES
ORIENTATION
SURFACES
TITANIUM COMPOUNDS
VANADIUM COMPOUNDS
WIRES