@article{SerranoMunozFritschMishurovaetal.2020,
  author    = {Serrano-Munoz, Itziar and Fritsch, Tobias and Mishurova, Tatiana and Trofimov, Anton and Apel, Daniel and Ulbricht, Alexander and Kromm, Arne and Hesse, Rene and Evans, Alexander and Bruno, Giovanni},
  title     = {On the interplay of microstructure and residual stress in LPBF IN718},
  series = {Journal of materials science},
  volume    = {56},
  journal   = {Journal of materials science},
  number    = {9},
  publisher = {Springer},
  address   = {New York},
  issn      = {0022-2461},
  doi       = {10.1007/s10853-020-05553-y},
  pages     = {5845 -- 5867},
  year      = {2020},
  abstract  = {The relationship between residual stresses and microstructure associated with a laser powder bed fusion (LPBF) IN718 alloy has been investigated on specimens produced with three different scanning strategies (unidirectional Y-scan, 90 degrees XY-scan, and 67 degrees Rot-scan). Synchrotron X-ray energy-dispersive diffraction (EDXRD) combined with optical profilometry was used to study residual stress (RS) distribution and distortion upon removal of the specimens from the baseplate. The microstructural characterization of both the bulk and the near-surface regions was conducted using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). On the top surfaces of the specimens, the highest RS values are observed in the Y-scan specimen and the lowest in the Rot-scan specimen, while the tendency is inversed on the side lateral surfaces. A considerable amount of RS remains in the specimens after their removal from the baseplate, especially in the Y- and Z-direction (short specimen dimension and building direction (BD), respectively). The distortion measured on the top surface following baseplate thinning and subsequent removal is mainly attributed to the amount of RS released in the build direction. Importantly, it is observed that the additive manufacturing microstructures challenge the use of classic theoretical models for the calculation of diffraction elastic constants (DEC) required for diffraction-based RS analysis. It is found that when the Reuss model is used for the calculation of RS for different crystal planes, as opposed to the conventionally used Kroner model, the results exhibit lower scatter. This is discussed in context of experimental measurements of DEC available in the literature for conventional and additively manufactured Ni-base alloys.},
  language  = {en}
}
@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{SchroederEvansMishurovaetal.2021,
  author    = {Schr{\"o}der, Jakob and Evans, Alexander and Mishurova, Tatiana and Ulbricht, Alexander and Sprengel, Maximilian and Serrano-Munoz, Itziar and Fritsch, Tobias and Kromm, Arne and Kannengießer, Thomas and Bruno, Giovanni},
  title     = {Diffraction-based residual stress characterization in laser additive manufacturing of metals},
  series = {Metals : open access journal},
  volume    = {11},
  journal   = {Metals : open access journal},
  number    = {11},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2075-4701},
  doi       = {10.3390/met11111830},
  pages     = {34},
  year      = {2021},
  abstract  = {Laser-based additive manufacturing methods allow the production of complex metal structures within a single manufacturing step. However, the localized heat input and the layer-wise manufacturing manner give rise to large thermal gradients. Therefore, large internal stress (IS) during the process (and consequently residual stress (RS) at the end of production) is generated within the parts. This IS or RS can either lead to distortion or cracking during fabrication or in-service part failure, respectively. With this in view, the knowledge on the magnitude and spatial distribution of RS is important to develop strategies for its mitigation. Specifically, diffraction-based methods allow the spatial resolved determination of RS in a non-destructive fashion. In this review, common diffraction-based methods to determine RS in laser-based additive manufactured parts are presented. In fact, the unique microstructures and textures associated to laser-based additive manufacturing processes pose metrological challenges. Based on the literature review, it is recommended to (a) use mechanically relaxed samples measured in several orientations as appropriate strain-free lattice spacing, instead of powder, (b) consider that an appropriate grain-interaction model to calculate diffraction-elastic constants is both material- and texture-dependent and may differ from the conventionally manufactured variant. Further metrological challenges are critically reviewed and future demands in this research field are discussed.},
  language  = {en}
}