@article{NadammalMishurovaFritschetal.2021,
  author    = {Nadammal, Naresh and Mishurova, Tatiana and Fritsch, Tobias and Serrano-Munoz, Itziar and Kromm, Arne and Haberland, Christoph and Portella, Pedro Dolabella and Bruno, Giovanni},
  title     = {Critical role of scan strategies on the development of microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing},
  series = {Additive manufacturing},
  volume    = {38},
  journal   = {Additive manufacturing},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2214-8604},
  doi       = {10.1016/j.addma.2020.101792},
  pages     = {13},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}
@article{PauzonMishurovaEvsevleevetal.2021,
  author    = {Pauzon, Camille and Mishurova, Tatiana and Evsevleev, Sergei and Dubiez-Le Goff, Sophie and Murugesan, Saravanakumar and Bruno, Giovanni and Hryha, Eduard},
  title     = {Residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion as a function of process atmosphere and component design},
  series = {Additive manufacturing},
  volume    = {47},
  journal   = {Additive manufacturing},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2214-8604},
  doi       = {10.1016/j.addma.2021.102340},
  pages     = {10},
  year      = {2021},
  abstract  = {The influence of the process gas, laser scan speed, and sample thickness on the build-up of residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion was studied. Pure argon and helium, as well as a mixture of those (30\% helium), were employed to establish process atmospheres with a low residual oxygen content of 100 ppm O-2. The results highlight that the subsurface residual stresses measured by X-ray diffraction were significantly lower in the thin samples (220 MPa) than in the cuboid samples (645 MPa). This difference was attributed to the shorter laser vector length, resulting in heat accumulation and thus in-situ stress relief. The addition of helium to the process gas did not introduce additional subsurface residual stresses in the simple geometries, even for the increased scanning speed. Finally, larger deflection was found in the cantilever built under helium (after removal from the baseplate), than in those produced under argon and an argon-helium mixture. This result demonstrates that complex designs involving large scanned areas could be subjected to higher residual stress when manufactured under helium due to the gas's high thermal conductivity, heat capacity, and thermal diffusivity.},
  language  = {en}
}