On two indentation hardness definitions

Zhiyong Li, Y. T. Cheng, Henry T. Yang, S. Chandrasekar

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


The difference between the contact area under load and the residual projected area of an indentation after complete unloading has been studied for various materials using finite element and dimensional analyses of cone indentation. The difference in the contact areas gives rise to two hardness values, one based on the contact area under load and another based upon the residual projected area. The effect of sinking-in, piling-up and elastic recovery on the residual contact area has been calculated for materials with different elastic properties and strain hardening characteristics. Based on this study, an estimation procedure is suggested for obtaining a more accurate value of the hardness under load from a measurement of the residual area of an indentation.

Original languageEnglish
Pages (from-to)124-130
Number of pages7
JournalSurface and Coatings Technology
Issue number2-3
StatePublished - May 15 2002

Bibliographical note

Funding Information:
We would like to thank Professor C.-M. Cheng and Dr. K.C. Taylor for helpful discussions. This research was partially supported by NSF grant DMI-9800920.


  • Contact area
  • Hardness
  • Indentation
  • Pile-up

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry


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