@misc{MuellerKupschLaquaietal.2018,
  author    = {M{\"u}ller, Bernd Randolf and Kupsch, Andreas and Laquai, Rene and Nellesen, Jens and Tillmann, Wolfgang and Kasperovich, Galina and Bruno, Giovanni},
  title     = {Microstructure Characterisation of Advanced Materials via 2D and 3D X-Ray Refraction Techniques},
  series = {Materials Science Forum},
  volume    = {941},
  journal   = {Materials Science Forum},
  publisher = {Trans Tech Publications Ltd},
  address   = {Zurich},
  isbn      = {978-3-0357-1208-7},
  issn      = {0255-5476},
  doi       = {10.4028/www.scientific.net/MSF.941.2401},
  pages     = {2401 -- 2406},
  year      = {2018},
  abstract  = {3D imaging techniques have an enormous potential to understand the microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this conference paper we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. We demonstrate showcases of ceramics and composite materials, where microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. We present in situ analysis of the damage evolution in an Al/Al2O3 metal matrix composite during tensile load and the identification of void formation (different kinds of defects, particularly unsintered powder hidden in pores, and small inhomogeneity's like cracks) in Ti64 parts produced by selective laser melting using synchrotron X-ray refraction radiography and tomography.},
  language  = {en}
}
@article{KojdaHofmannGostkowskaLekneretal.2022,
  author    = {Kojda, Danny and Hofmann, Tommy and Gostkowska-Lekner, Natalia Katarzyna and Habicht, Klaus},
  title     = {Characterization and modeling of the temperature-dependent thermal conductivity in sintered porous silicon-aluminum nanomaterials},
  series = {Nano research},
  volume    = {15},
  journal   = {Nano research},
  number    = {6},
  publisher = {Tsinghua Univ. Press},
  address   = {Beijing},
  issn      = {1998-0124},
  doi       = {10.1007/s12274-022-4123-y},
  pages     = {5663 -- 5670},
  year      = {2022},
  abstract  = {Nanostructured silicon and silicon-aluminum compounds are synthesized by a novel synthesis strategy based on spark plasma sintering (SPS) of silicon nanopowder, mesoporous silicon (pSi), and aluminum nanopowder. The interplay of metal-assisted crystallization and inherent porosity is exploited to largely suppress thermal conductivity. Morphology and temperature-dependent thermal conductivity studies allow us to elucidate the impact of porosity and nanostructure on the macroscopic heat transport. Analytic electron microscopy along with quantitative image analysis is applied to characterize the sample morphology in terms of domain size and interpore distance distributions. We demonstrate that nanostructured domains and high porosity can be maintained in densified mesoporous silicon samples. In contrast, strong grain growth is observed for sintered nanopowders under similar sintering conditions. We observe that aluminum agglomerations induce local grain growth, while aluminum diffusion is observed in porous silicon and dispersed nanoparticles. A detailed analysis of the measured thermal conductivity between 300 and 773 K allows us to distinguish the effect of reduced thermal conductivity caused by porosity from the reduction induced by phonon scattering at nanosized domains. With a modified Landauer/Lundstrom approach the relative thermal conductivity and the scattering length are extracted. The relative thermal conductivity confirms the applicability of Kirkpatrick's effective medium theory. The extracted scattering lengths are in excellent agreement with the harmonic mean of log-normal distributed domain sizes and the interpore distances combined by Matthiessen's rule.},
  language  = {en}
}