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Journal of Phase Equilibria

, Volume 15, Issue 3, pp 279–284 | Cite as

Phase equilibria in Ti3Al-Nb alloys at 1000 °C

  • S. G. Kumar
  • R. G. Reddy
  • L. Brewer
Article

Abstract

Titanium aluminides are considered to be the future high-temperature structural materials for turbine applications. Major focus is on α2Ti3Al based and γTiAl based alloys. Niobium additions to Ti3Al alloys is found to improve the room-temperature ductility. Thus phase equilibria in Ti-Al-Nb system is of practical significance with regard to their processing and high-temperature phase stability characteristics. In the present research, four alloys with compositions Ti-22Al-12Nb, Ti-21A1-16Nb, Ti-20Al-20Nb, and Ti-25Al-25Nb (all in atom percent) were equilibrated at 1000 °C for 225 hours and then quenched in water. The quenched alloys were characterized for phase relations by optical microscopy, X-ray diffraction (XRD), and electron probe microanalysis (EPMA). Based on the phase analysis, the ternary isotherm of the Ti-Al-Nb system at 1000 °C was constructed on the Ti3Al-rich side. The orthorhombic Ti2AlNb phase was observed in the sample with Ti-25Al-25Nb composition signifying the presence of this phase at 1000 °C.

Keywords

Phase Equilibrium Niobium Elemental Powder Titanium Aluminides Niobium Content 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© ASM International 1994

Authors and Affiliations

  • S. G. Kumar
    • 1
  • R. G. Reddy
    • 1
  • L. Brewer
    • 2
  1. 1.Dept. of Chemical and Metallurgical Engineering/MS 170University of NevadaReno
  2. 2.Lawrence Berkeley LaboratoryUniversity of CaliforniaBerkeley

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