A new approach for studying mechanical properties of thin surface layers affected by manufacturing processes

S. P. Moylan, S. Kompella, S. Chandrasekar, T. N. Farris

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Nano-indentation has become an important tool in the study of mechanical properties of solids at small length scales, ever since its formulation as a technique in the early 1980s.* The small size of an indentation, typically one micrometer or less in surface extent, makes it a potentially attractive tool also for the quantitative study of the characteristics of surface layers in monolithic solids. Here, we report results from a study in which nano-indentation has been combined with taper-sectioning to analyze the mechanical properties of thin surface layers affected by manufacturing processes. The so-called white etching layer (WL) produced in steel surfaces by machining and abrasion is characterized. The WL is found to have a hardness in the range of 11.5-16.2 GPa, which is significantly greater than that of untempered martensite produced by heat treatment processes. These hardness values are close to those measured on steel piano wires. The so-called "burn-layer" produced on ground surfaces of steels is found to have a hardness distribution very similar to that of a white layer, suggesting that the two layers are of the same type. Localized hardening and softening of surface layers, over spatial extents of a few micrometers, caused by material removal processes are accurately resolved by the combined use of nano-indentation and taper-sectioning. The taper-sectioning/nano-indentation approach is also shown to be a good procedure for characterizing the hardness of PVD-TiN films deposited onto hard metal substrates.

Original languageEnglish (US)
Pages (from-to)310-315
Number of pages6
JournalJournal of Manufacturing Science and Engineering, Transactions of the ASME
Volume125
Issue number2
DOIs
StatePublished - May 1 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Control and Systems Engineering
  • Mechanical Engineering
  • Computer Science Applications
  • Industrial and Manufacturing Engineering

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