In situ determination of stresses from time-of-flight neutron transmission spectra

Axel Steuwer, Javier Roberto Santisteban, Philip J. Withers, Lyndon Edwards, Mike E. Fitzpatrick

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

The pulsed neutron transmission diffraction technique exploits the sharp steps in intensity (Bragg edges) appearing in the transmitted spectra of thermal neutrons through polycrystalline materials. In this paper the positions of these edges acquired by the time-of-flight (TOF) technique are used to measure accurately the interplanar lattice distances to a resolution of Δd/d ≃ 10-4 of specimens subjected to in situ uniaxial tensile loading. The sensitivity of the method is assessed for elastically isotropic (b.c.c. ferritic) and anisotropic (f.c.c. austenitic) polycrystalline specimens of negligible and moderately textured steels. For the more anisotropic austenitic steel, the elastic anisotropy is studied with regard to a Pawley refinement, and compared with previous results from conventional neutron diffraction experiments on the same material. It is shown that the method can be used to determine anisotropic strains, diffraction elastic constants, the residual and applied stress state as well as the unstrained lattice parameter by recording transmission spectra at different specimen inclinations, by complete analogy with the sin2ψ technique frequently used in X-ray raphy diffraction. The technique is shown to deliver reliable measures of strain even in the case of moderate texture and elastic anisotropy.

Original languageEnglish
Pages (from-to)1159-1168
Number of pages10
JournalJournal of Applied Crystallography
Volume36
Issue number5
DOIs
Publication statusPublished - 1 Oct 2003
Externally publishedYes

Keywords

  • neutron transmission
  • time of flight
  • residual stress
  • strain
  • elastic anisotropy

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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