Investigation of hardness and fracture toughness properties of Fe/VC multilayer coatings with coherent interfaces

Chen Wang, Julio Miranda Pureza, Yanqing Yang, Yip Wah Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Fe/VC multilayer coatings with a fixed bilayer period (Λ = 8 nm) and variable Fe fraction (ΛFe/Λ ranging from 0.6 to 0.9) were deposited on Si substrates via dc magnetron sputtering. X-Ray diffraction and transmission electron microscopy showed the nanoscale layer structure of these coatings. High-resolution transmission electron microscopy imaging revealed the formation of coherent interfaces between Fe and VC (100). Throughout the entire range of Fe fractions investigated in this study, the hardness was enhanced over the rule-of-mixture trend line. Even at Fe fraction of 0.9, the hardness value was 16.3 GPa, enhanced by about 80% over the rule-of-mixture value of 9 GPa. While all Fe/VC coatings investigated in this work have statistically the same hardness, Fe/VC coating with Fe fraction of 90% has almost twice the fracture toughness of the other Fe/VC coatings. We attribute this enhanced toughness to the favorable generation of dislocations in the Fe layers and their activation by coherency strain emanating from Fe/VC interfaces. This study also demonstrates that H/E and H3/E2 are not good proxies for the toughness of these coatings.

Original languageEnglish (US)
Pages (from-to)179-184
Number of pages6
JournalSurface and Coatings Technology
StatePublished - Feb 25 2016


  • Fracture toughness
  • Hardness
  • Magnetron sputtering
  • Multilayers
  • Nanoindentation

ASJC Scopus subject areas

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


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