TY  - JOUR
A1  - Mishurova, Tatiana
A1  - Sydow, Benjamin
A1  - Thiede, Tobias
A1  - Sizova, Irina
A1  - Ulbricht, Alexander
A1  - Bambach, Markus
A1  - Bruno, Giovanni
T1  - Residual stress and microstructure of a Ti-6Al-4V Wire Arc Additive Manufacturing hybrid demonstrator
JF  - Metals
N2  - Wire Arc Additive Manufacturing (WAAM) features high deposition rates and, thus, allows production of large components that are relevant for aerospace applications. However, a lot of aerospace parts are currently produced by forging or machining alone to ensure fast production and to obtain good mechanical properties; the use of these conventional process routes causes high tooling and material costs. A hybrid approach (a combination of forging and WAAM) allows making production more efficient. In this fashion, further structural or functional features can be built in any direction without using additional tools for every part. By using a combination of forging basic geometries with one tool set and adding the functional features by means of WAAM, the tool costs and material waste can be reduced compared to either completely forged or machined parts. One of the factors influencing the structural integrity of additively manufactured parts are (high) residual stresses, generated during the build process. In this study, the triaxial residual stress profiles in a hybrid WAAM part are reported, as determined by neutron diffraction. The analysis is complemented by microstructural investigations, showing a gradient of microstructure (shape and size of grains) along the part height. The highest residual stresses were found in the transition zone (between WAAM and forged part). The total stress range showed to be lower than expected for WAAM components. This could be explained by the thermal history of the component.
KW  - residual stress
KW  - WAAM
KW  - Ti-6Al-4V
KW  - additive manufacturing
KW  - neutron
KW  - diffraction
KW  - hybrid manufacturing
Y1  - 2020
U6  - https://doi.org/10.3390/met10060701
SN  - 2075-4701
VL  - 10
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Serrano-Munoz, Itziar
A1  - Mishurova, Tatiana
A1  - Thiede, Tobias
A1  - Sprengel, Maximilian
A1  - Kromm, Arne
A1  - Nadammal, Naresh
A1  - Nolze, Gert
A1  - Saliwan-Neumann, Romeo
A1  - Evans, Alexander
A1  - Bruno, Giovanni
T1  - The residual stress in as-built laser powder bed fusion IN718 alloy as a consequence of the scanning strategy induced microstructure
JF  - Scientific reports
N2  - The effect of two types of scanning strategies on the grain structure and build-up of Residual Stress (RS) has been investigated in an as-built IN718 alloy produced by Laser Powder Bed Fusion (LPBF). The RS state has been investigated by X-ray diffraction techniques. The microstructural characterization was performed principally by Electron Backscatter Diffraction (EBSD), where the application of a post-measurement refinement technique enables small misorientations (< 2 degrees) to be resolved. Kernel average misorientation (KAM) distributions indicate that preferably oriented columnar grains contain higher levels of misorientation, when compared to elongated grains with lower texture. The KAM distributions combined with X-ray diffraction stress maps infer that the increased misorientation is induced via plastic deformation driven by the thermal stresses, acting to self-relieve stress. The possibility of obtaining lower RS states in the build direction as a consequence of the influence of the microstructure should be considered when envisaging scanning strategies aimed at the mitigation of RS.
KW  - EBSD
KW  - components
KW  - deposition
KW  - diffraction
KW  - distortion
KW  - heat-treatment
KW  - mechanical properties
KW  - melting slm
KW  - superalloys
KW  - texture
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-71112-9
SN  - 2045-2322
VL  - 10
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  -