In situ high-energy X-ray diffraction study of tensile deformation of neutron-irradiated polycrystalline Fe-9%Cr alloy

Xuan Zhang, Meimei Li, Jun Sang Park, Peter Kenesei, Jonathan Almer, Chi Xu, James F. Stubbins

Research output: Contribution to journalArticle

Abstract

The effect of neutron irradiation on tensile deformation of a Fe-9wt%Cr alloy was investigated using in situ high-energy synchrotron X-ray diffraction during room-temperature uniaxial tension tests. New insights into the deformation mechanisms were obtained through the measurements of lattice strain evolution and the analysis of diffraction peak broadening using the modified Williamson-Hall method. Two neutron-irradiated specimens, one irradiated at 300 °C to 0.01 dpa and the other at 450 °C to 0.01 dpa, were tested along with an unirradiated specimen. The macroscopic stress–strain curves of the irradiated specimens showed increased strength, reduced ductility and reduced work-hardening exponent compared to the unirradiated specimen. The evolutions of the lattice strain, the dislocation density and the coherent scattering domain size in the deformation process revealed different roles of the submicroscopic defects in the 300 °C/0.01 dpa specimen and the nanometer-sized dislocation loops in the 450 °C/0.01 dpa specimen; the dislocation loops were more effective in dislocation pinning. While the work hardening rate of stage II was unaffected by irradiation, significant dynamic recovery in stage III in the irradiated specimens led to the early onset of necking without stage IV as observed in the unirradiated specimen.

Original languageEnglish (US)
Pages (from-to)67-76
Number of pages10
JournalActa Materialia
Volume126
DOIs
StatePublished - Mar 1 2017

Keywords

  • In situ X-ray diffraction
  • Neutron irradiation
  • Tensile deformation
  • Work hardening stages

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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