Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography

Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional character-ization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure charac-terization methods towards the meso-and macroscale.(c) 2022 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

In this study, wavelength-selective neutron tomography was used for three-dimensional characterization of phase distributions in metastable austenitic stainless steel samples. It was found that accurate quantitative results can be obtained if the samples do not exhibit significant preferential grain orientation. The results obtained by neutron tomography were verified and explained using optical microscopy, electron backscatter diffraction, and finite element modeling. The study demonstrates the capability of neutron tomography to extend microstructure characterization methods to the meso- and macroscale.