Phase transformation during aging and resulting mechanical properties of two Ti-Nb-Ta-Zr alloys

S. J. Li, R. Yang, M. Niinomi, Y. L. Hao, Y. Y. Cui, Z. X. Guo

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Phase transformations and mechanical properties of both Ti-29Nb-13Ta-4·6Zr and Ti-39Nb-13Ta-4·6Zr (wt-%) alloys were investigated. The microstructure of the 29Nb alloy is sensitive to solution and aging treatment. Ice water quenching from the solution treatment temperature resulted in (β+α″) microstructure but air or furnace cooling led to a mixture of (β+ω). The formation of the orthorhombic α″ martensite thus suppresses ω formation in the ice water quenched 29Nb alloy, Cooling rate from the solution treatment temperature also has a significant effect on the formation of α and ω phases during subsequent isothermal aging below the ω start temperature: slow cooling enhances ω but depresses α formation. This cooling rate dependence of aged microstructure was attributed to α″ martensite acting as precursor of thus phase, thus providing a low energy path to the precipitation of α at the expense of ω. Phase transformation in the 39Nb alloy is more sluggish than that in the 29Nb alloy, owing to the presence of the higher content of β stabiliser Nb. For the 29Nb alloy, Young's modulus and mechanical properties are sensitive to the fraction of phases, and change significantly during aging, in contrast with the 39Nb alloy.

Original languageEnglish
Pages (from-to)678-686
Number of pages9
JournalMaterials Science and Technology
Volume21
Issue number6
DOIs
Publication statusPublished - 2005 Jun 1

Keywords

  • Mechanical properties
  • Metastable β titanium alloy
  • Phase transformation
  • Young's modulus

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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