@article{StegemannCabezaPelkneretal.2018,
  author    = {Stegemann, Robert and Cabeza, Sandra and Pelkner, Matthias and Lyamkin, Viktor and Pittner, Andreas and Werner, Daniel and Wimpory, Robert and Boin, Mirko and Kreutzbruck, Marc and Bruno, Giovanni},
  title     = {Influence of the microstructure on magnetic stray fields of low-carbon steel welds},
  series = {Journal of Nondestructive Evaluation},
  volume    = {37},
  journal   = {Journal of Nondestructive Evaluation},
  number    = {3},
  publisher = {Springer},
  address   = {New York},
  issn      = {0195-9298},
  doi       = {10.1007/s10921-018-0522-0},
  pages     = {18},
  year      = {2018},
  abstract  = {This study examines the relationship between the magnetic mesostructure with the microstructure of low carbon steel tungsten inert gas welds. Optical microscopy revealed variation in the microstructure of the parent material, in the heat affected and fusion zones, correlating with distinctive changes in the local magnetic stray fields measured with high spatial resolution giant magneto resistance sensors. In the vicinity of the heat affected zone high residual stresses were found using neutron diffraction. Notably, the gradients of von Mises stress and triaxial magnetic stray field modulus follow the same tendency transverse to the weld. In contrast, micro-X-ray fluorescence characterization indicated that local changes in element composition had no independent effect on magnetic stray fields.},
  language  = {en}
}
@article{MishurovaStegemannLyamkinetal.2022,
  author    = {Mishurova, Tatiana and Stegemann, Robert and Lyamkin, Viktor and Cabeza, Sandra and Evsevleev, Sergei and Pelkner, Matthias and Bruno, Giovanni},
  title     = {Subsurface and bulk residual stress analysis of S235JRC+C Steel TIG weld by diffraction and magnetic stray field measurements},
  series = {Experimental mechanics : an international journal of the Society for Experimental Mechanics},
  volume    = {62},
  journal   = {Experimental mechanics : an international journal of the Society for Experimental Mechanics},
  number    = {6},
  publisher = {Springer},
  address   = {New York},
  issn      = {0014-4851},
  doi       = {10.1007/s11340-022-00841-x},
  pages     = {1017 -- 1025},
  year      = {2022},
  abstract  = {Background Due to physical coupling between mechanical stress and magnetization in ferromagnetic materials, it is assumed in the literature that the distribution of the magnetic stray field corresponds to the internal (residual) stress of the specimen. The correlation is, however, not trivial, since the magnetic stray field is also influenced by the microstructure and the geometry of component. The understanding of the correlation between residual stress and magnetic stray field could help to evaluate the integrity of welded components. Objective This study aims at understanding the possible correlation of subsurface and bulk residual stress with magnetic stray field in a low carbon steel weld. Methods The residual stress was determined by synchrotron X-ray diffraction (SXRD, subsurface region) and by neutron diffraction (ND, bulk region). SXRD possesses a higher spatial resolution than ND. Magnetic stray fields were mapped by utilizing high-spatial-resolution giant magneto resistance (GMR) sensors. Results The subsurface residual stress overall correlates better with the magnetic stray field distribution than the bulk stress. This correlation is especially visible in the regions outside the heat affected zone, where the influence of the microstructural features is less pronounced but steep residual stress gradients are present. Conclusions It was demonstrated that the localized stray field sources without any obvious microstructural variations are associated with steep stress gradients. The good correlation between subsurface residual stress and magnetic signal indicates that the source of the magnetic stray fields is to be found in the range of the penetration depth of the SXRD measurements.},
  language  = {en}
}