Microstructures and tensile properties of massively transformed and aged Ti46Al8Nb and Ti46Al8Ta alloys

Saage, Holger; Huang, Aijun; Hu, D.; Loretto, M. H.; Wu, Xinhua

doi:10.1016/j.intermet.2008.09.006

Cited by 103 publications

(76 citation statements)

References 12 publications

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“…Recent eorts in the development of new low--weight intermetallic TiAl-based materials for low pressure turbine blades has led to the design of a new Ti46Al8Ta [at.%] alloy [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…The convoluted microstructure is formed by precipitation of the α and/or α 2 phases on four equivalent {111} planes of the massively transformed γ M during annealing and subsequent cooling from the two-phase α + γ eld [2]. This new alloy shows promising castability and has a relatively large processing window to achieve the α 2 + γ microstructure during the heat treatments.…”

Section: Introductionmentioning

confidence: 99%

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Creep Deformation of Intermetallic TiAl-Based Alloy

Lapin

Staneková

2012

Acta Phys. Pol. A

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In the present work, the creep deformation behaviour of a new cast intermetallic Ti46Al8Ta [at.%] alloy is analysed. Constant load tensile creep tests were performed at initial applied stresses ranging from 200 to 400 MPa in the temperature range from 973 to 1073 K. The measured creep deformation curves are analysed and the observed deviations from calculated curves are discussed based on microstructural changes observed in the studied alloy during creep. The kinetics of creep deformation are evaluated in terms of the true activation energy for creep and the stress exponent. Creep damage initiation and propagation leading to the fracture of the creep specimens are characterized as functions of the applied stress and temperature.

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“…Recent eorts in the development of new low--weight intermetallic TiAl-based materials for low pressure turbine blades has led to the design of a new Ti46Al8Ta [at.%] alloy [1,2].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Creep Deformation of Intermetallic TiAl-Based Alloy

Lapin

Staneková

2012

Acta Phys. Pol. A

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“…1b. As shown by Saage et al [7], such "convoluted" type of microstructure is formed by precipitation of the α and/or α 2 phases on four equivalent {111} planes of the massively transformed γ M during the second HIP-ing at 1260…”

Section: Methodsmentioning

confidence: 92%

“…These elements partition between α and γ phases when forming the α + γ lamellar microstructure and this requirement for their diffusion slows down the lamellar transformation. Based on this concept, a new "airhardenable" Ti-46Al--8Ta (at.%) alloy requiring only air cooling from single α phase field to form massive γ M was designed [7,8] within the European integrated project IMPRESS [9]. This alloy shows promising castability, mechanical properties, and relatively large processing window to achieve α 2 (Ti 3 Al) + γ(TiAl) microstructure during heat treatments [8].…”

Section: Introductionmentioning

confidence: 99%

Long term microstructural stability of intermetallic Ti-46Al-8Ta alloy during ageing at temperatures of 700-800 °C

Lapin¹,

Pelachová²,

Staneková³

et al. 2010

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The lamellar α2(Ti3Al) + γ(TiAl) microstructure of intermetallic Ti-46Al-8Ta (at.%) alloy is unstable and transforms to α2 + γ + τ type at temperatures ranging from 700 to 800• C during long-term ageing up to 10000 h. TEM observations and selected area diffraction patterns show that the ternary τ phase with B82 type structure (space group P63/mmc) is preferentially formed along the grain and lamellar colony boundaries. Volume fractions of the τ and γ phases increase with increasing ageing time at the expense of decreasing volume fraction of the α2 phase at all ageing temperatures. The lattice parameters of the α2 and γ phases change during ageing when compared with those of the as-received alloy. The ageing temperatures have no measurable effect on the lattice parameters of the coexisting α2, γ and τ phases after ageing for 10000 h. The Vickers microhardness decreases reaching a minimum after ageing for about 500 h and then increases to peak values with increasing ageing time. The ageing time longer than 1500 h leads to a continuous softening of the alloy at all ageing temperatures.K e y w o r d s : titanium aluminides, TiAl, phase identification, microstructure, diffraction

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“…Hu et al [3] showed that Ta has low diusion coecients in both α (Ti-based solid solution) and γ phases and favours the massive transformation over the lamellar formation at low cooling rates. Based on this concept, an air--hardenable Ti46Al8Ta [at.%] alloy, requiring only air cooling from the single α phase eld to reduce the grain size of the cast components via formation of massive γ M (TiAl), was designed [3,4]. Potential industrial applications of this alloy are conditioned by optimisation of processing techniques [5,6] and a more complex understanding of mechanical properties including creep at operating temperatures.…”

Section: Introductionmentioning

confidence: 99%