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  - 
TY  - JOUR
A1  - Nadammal, Naresh
A1  - Mishurova, Tatiana
A1  - Fritsch, Tobias
A1  - Serrano-Munoz, Itziar
A1  - Kromm, Arne
A1  - Haberland, Christoph
A1  - Portella, Pedro Dolabella
A1  - Bruno, Giovanni
T1  - Critical role of scan strategies on the development of microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing
JF  - Additive manufacturing
N2  - Laser based powder bed fusion additive manufacturing offers the flexibility to incorporate standard and user-defined scan strategies in a layer or in between the layers for the customized fabrication of metallic components. In the present study, four different scan strategies and their impact on the development of microstructure, texture, and residual stresses in laser powder bed fusion additive manufacturing of a nickel-based superalloy Inconel 718 was investigated. Light microscopy, scanning electron microscopy combined with electron back-scatter diffraction, and neutron diffraction were used as the characterization tools. Strong textures with epitaxially grown columnar grains were observed along the build direction for the two individual scan strategies. Patterns depicting the respective scan strategies were visible in the build plane, which dictated the microstructure development in the other planes. An alternating strategy combining the individual strategies in the successive layers and a 67 degrees rotational strategy weakened the texture by forming finer micro-structural features. Von Mises equivalent stress plots revealed lower stress values and gradients, which translates as lower distortions for the alternating and rotational strategies. Overall results confirmed the scope for manipulating the microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing by effectively controlling the scan strategies.
KW  - Additive manufacturing
KW  - Laser powder bed fusion
KW  - Nickel-based
KW  - superalloys
KW  - Scan strategies
KW  - Residual stresses
KW  - Microstructure and
KW  - texture
Y1  - 2021
U6  - https://doi.org/10.1016/j.addma.2020.101792
SN  - 2214-8604
VL  - 38
PB  - Elsevier
CY  - Amsterdam
ER  -