Probing the meso- and macroscale with advanced neutron imaging techniques

Probing the meso- and macroscale with advanced neutron imaging techniques

Neutron imaging has experienced tremendous progress over the last decade especially by taking advantage of new contrast mechanisms. This presentation will give an overview of activities at reactor and spallation sources, focusing on engineering applications where neutron imaging and diffraction techniques can provide information on the meso- and macroscale in bulk samples (cm dimension), representing the global mechanical properties.

Emphasis will be given to diffraction contrast imaging that allows nondestructive crystallographic (phase-, texture-, strain-) imaging in 2D and 3D. Tomographic results showing the distribution of Austenite and Martensite in (TRIP) steel samples after being subjected to tensile and torsional deformation will be discussed in detail. Typical results involve samples with circular or rectangular cross sections (>50mm2) while providing spatial sensitivity that is averaged over several grains (typically 200-300μm). While the quantitative tomography of phase distributions is currently limited to random and mildly textured samples, the same methodology can be applied to visualize local texture evolutions and to detect inhomogeneities.

The European Spallation Source (currently under construction in Sweden) will be the most powerful neutron source and unlock further potential in neutron imaging. Ongoing method development is targeted to detect features (including cracks, precipitates and e.g. hydrogen traps) covering all length scales from nanometers to the direct spatial resolution (currently 10μm) and to use complementary diffraction detectors with the goal to provide quantitative phase-, strain- and texture distributions (3D-ND).

Dr. R. Woracek

European Spallation Source ESS
AB SE-221-00 Lund

Sweden

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