Scanning wide-angle neutron diffraction and its application to local structures investigations in stainless steel

Kenji Ohoyama, Kazuyuki Isawa, Kazuyoshi Yamada

Research output: Contribution to journalArticle

Abstract

We applied a spatial scanning measurement technique to neutron diffraction on a powder diffractometer, and performed scanning wide-angle neutron diffraction (SWND) experiments to investigate local structures of materials. The SWND technique has an advantage that one can observe a diffraction pattern over a wide scattering angle range, so that the positional dependence of local crystal structures can be measured for practical durations. Moreover, because neutrons have a larger penetration depth, on the order of a few cm, than X-rays, the SWND technique provides structural information even in internal regions of materials. We succeeded in observing positional dependence of diffraction patterns from small areas (approximately 2 × 5 mm2) of a type-304 stainless steel plate with a dimension of 19.5 × 50 × 4.7 mm3 subjected to a mechanical tensile strain of 90% of the 0.2% offset yield strength. In the SWND experiments, we confirmed that the crystallographic circumstance in the strain-loaded type-304 stainless steel is not homogeneous. For instance, we observed positional deviation in the grain direction of the master-alloy austenite phase, and local distribution of the stress induced martensite phase. The SWND technique is a particularly important probe for estimating the stress-induced phase, because it on-destructively observes even the inside of bulk materials.

Original languageEnglish
Pages (from-to)7925-7931
Number of pages7
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume46
Issue number12
DOIs
Publication statusPublished - 2007 Dec 6

Keywords

  • Scanning SQUID microscopy
  • Scanning neutron diffraction
  • Structural fluctuation
  • Type-304 stainless steel

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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