Surface hardening treatment in use of CO gas and post-heat treatment in C.P. titanium and titanium alloys

Y. Z. Kim, T. Murakami, T. Narushima, Y. Iguchi, C. Ouchi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Citations (Scopus)


Surface hardening treatment of titanium materials in use of CO gas was studied including investigation of post heat treatment under vacuum. C.P. titanium, α+β type SP-700 alloy with Ti-4.5%Al-3%V-2%Mo-2%Fe and β type alloy with Ti-15%Mo-5%Zr-3%Al were used. Surface hardening was conducted by heating these materials at 1073K for 21.6ks in Ar-5%CO gas. Subsequently, specimens subjected to surface hardening were heated at 1073k for various time periods under vacuum. While the maximum surface hardness value was the largest in C.P. titanium and the least in SP-700 alloy, hardening layer thickness was the thickest in β type alloy and the thinnest in C.P. titanium. Surface hardening in C.P. titanium was brought about by solid solution hardening due to oxygen and carbon. Enrichment of these elements in the surface layer of both titanium alloys caused continuous variations of the microstructure such as β to a+β, or their volume fractions in the surface hardening layer. Post heat treatment at 1073K increased the maximum surface hardness and hardening layer thickness with an extension of the heating time in C.P. titanium, but the surface maximum hardness decreased continuously in β type titanium alloy. Post heat treatment could remove the thin oxide layer formed by surface hardening treatment.

Original languageEnglish
Title of host publicationHeat Treatment of Materials, AHTM ' 05 - Proceedings of the 3rd Asian Conference on Heat Treatment of Materials
PublisherTrans Tech Publications Ltd
Number of pages6
ISBN (Print)9783908451259
Publication statusPublished - 2006
Event3rd Asian Conference on Heat Treatment of Materials,(AHTM '05) - Gyeongju, Korea, Republic of
Duration: 2005 Nov 102005 Nov 12

Publication series

NameSolid State Phenomena
ISSN (Print)1012-0394


Other3rd Asian Conference on Heat Treatment of Materials,(AHTM '05)
Country/TerritoryKorea, Republic of


  • C.p. Titaniurnsp-700 alloy
  • Carbon
  • Co gas
  • Oxygen
  • Solid solution hardening
  • Srface hardening
  • Ti-15%mo-3%ai alloy

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics


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