In situ measurement of the strains within a mechanically loaded polygranular graphite

Research output: Contribution to journalArticlepeer-review


  • T. J. Marrow
  • D. Liu
  • S. M. Barhli
  • L. Saucedo Mora
  • Ye Vertyagina
  • C. Reinhard
  • S. Kabra
  • P. E.J. Flewitt
  • D. J. Smith

Colleges, School and Institutes

External organisations

  • Diamond Light Source


Neutron diffraction and synchrotron X-ray diffraction and imaging have been applied to study, in situ, the mechanical response to tensile and bending loading of polygranular Gilsocarbon nuclear grade near-isotropic graphite (grade IM1-24). Digital image correlation of X-ray radiographs and digital volume correlation of tomographs allow measurement of bulk elastic moduli and examination of the heterogeneity of deformation in the microstructure. Both the neutron and X-ray studies show the application of tensile strain reduces the bulk elastic modulus. A permanent set is observed to develop with applied tensile strain. The elastic strains within the graphite crystals were measured by diffraction; a cross-correlation analysis method has been applied for greater speed, robustness and improved precision in the measurement of the change in basal plane separation distance. In compression, a linear relation is observed between the elastic strains in the graphite crystals and the applied strain. In tension, this relationship is non-linear. The results are discussed with respect to the distribution of elastic and inelastic strain within the graphite microstructure. It is deduced that the significant residual elastic strains in the as-manufactured graphite are relaxed by microcracking as tensile strain is applied.


Original languageEnglish
Pages (from-to)285-302
Number of pages18
Early online date18 Sep 2015
Publication statusPublished - 1 Jan 2016

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