Isothermal oxidation behaviour of beta gamma powder metallurgy TiAl-4Nb-3Mn alloys

Download
  1. Get@NRC: Isothermal oxidation behaviour of beta gamma powder metallurgy TiAl-4Nb-3Mn alloys (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1179/000844311X13112418376129
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleCanadian Metallurgical Quarterly
ISSN0008-4433
Volume50
Issue4
Pages416424; # of pages: 9
SubjectDiffusion zones; Exposure-time; Heat-treated specimens; Higher temperatures; Isothermal oxidation; Isothermal oxidations; Mixed layer; Outward diffusion; Oxidation mechanisms; Powder metallurgy process; Ti-48Al alloy; TiO; Titanium aluminide; White layer; Activation energy; Alloys; Aluminum; Cerium alloys; Manganese; Niobium; Oxidation; Powder metallurgy; Reaction intermediates; Titanium; Titanium compounds; Titanium dioxide; Tungsten; Titanium alloys
AbstractA new TiAl-4Nb-3Mn beta gamma alloy was synthesised by a powder metallurgy process. HIPed and vacuum heat treated specimens were isothermally oxidised at 800 and 900°C in air up to 500 h. The TiAl-4Nb-3Mn alloys oxidised parabolically up to 500 h at both 800 and 900°C. The oxides consisted of outer TiO2 layer, intermediate Al2O3 layer and inner TiO2 rich mixed layer and the oxidation mechanisms of the alloy were identical at both temperatures. During oxidation, the degradation of a2 lamellae in the vicinity of the interface forms a diffusion zone (lamellar depleted zone) leading to the formation of Nb and Mn rich white layers just below the interface by outward diffusion of Nb and Mn which are released from breakdown of α2 lamellae. As exposure time increases, Nb begins to diffuse earlier than Mn and diffuses more actively at higher temperature. The activation energy for oxidation of TiAl-4Nb-3Mn alloy was lower than that of Ti-48Al alloy and was higher than those of Ti-48Al-2Nb-2Cr and Ti-48Al-2Nb-2Cr-W alloys. © 2011 Canadian Institute of Mining, Metallurgy and Petroleum.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); Aerospace (AERO-AERO)
Peer reviewedYes
NPARC number21271210
Export citationExport as RIS
Report a correctionReport a correction
Record identifier960b949e-cccc-4300-84a2-3f1a78bf1cf6
Record created2014-03-24
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)