Effect of Processing on Nix-Gao Bilinear Indentation Results Obtained for High Purity Iron

Prasad Pramod Soman, Erik Gregory Herbert, Katerina E Aifantis, Stephen A. Hackney

Research output: Contribution to journalArticle

1 Scopus citations


Instrumented indentation of a high purity Fe surface with unresolved surface deformation due to mechanical polishing is compared to the same grain surface annealed at increasing time and temperature. The differences in indentation size effect behavior with annealing are correlated with hardness and electron backscatter diffraction measurements as independent measures of surface layer deformation. It is found that the Nix Gao plot evolves from non-linear (bilinear) towards the predicted linear relationship as the surface deformation is removed. The experimental observations are rationalized by inclusion of a depth dependent, polishing induced forest dislocation density within the Nix-Gao model.

Original languageEnglish (US)
Pages (from-to)477-486
Number of pages10
JournalMRS Advances
Issue number8-9
Publication statusPublished - Jan 1 2018
Externally publishedYes



  • grain boundaries
  • hardness
  • nano-indentation

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Science(all)
  • Condensed Matter Physics

Cite this