Anomalous surface deformation of sapphire clarified by 3D-FEM simulation of the nanoindentation

Roman Nowak, Timo Manninen, Chunliang Li, Kari Heiskanen, Simo-Pekka Hannula, Veikko Lindroos, Tetsuo Soga, Fusahito Yoshida

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)


This work clarifies the origin of anomalous surface deformation reflected by peculiar surface patterns around indentation impressions on various crystallographic planes of sapphire. The three-dimensional finite element simulation (3D-FEM) of nanoindentation in Al2O3 crystal allowed the authors to localize the regions in which various kinds of twinning and slip are most prone to be activated. The work provides a novel approach to the “hardness anisotropy”, which was modeled so far using a modified uniaxial-stress approximation of this essentially 3D, non-isotropic contact problem. The calculated results enabled the authors to unravel the asymmetric surface deformation detected on prismatic planes by the high-resolution microscopy, which cannot be explained using simple crystallographic considerations.
Original languageEnglish
Pages (from-to)265-271
JournalJSME International Journal, Series 1: Solid Mechanics, Strength of Materials
Issue number3
Publication statusPublished - 2003
MoE publication typeA1 Journal article-refereed


  • nanoindentation
  • twinning
  • slip
  • FEM simulation
  • sapphire
  • anisotropic contact problem


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