Journals →  Tsvetnye Metally →  2015 →  #10 →  Back

METAL PROCESSING
ArticleName Calculation analysis of phase diagrams of ternary Al – Ti – X systems in the area of γ-alloys on the basis of titanium aluminide
DOI 10.17580/tsm.2015.10.06
ArticleAuthor Dashkevich N. I., Belov N. A., Beltyukova S. O.
ArticleAuthorData

Interdepartmental analytic center, Moscow, Russia:

N. I. Dashkevich, Area manager


National University of Science and Technology “MISiS”, Moscow, Russia:
N. A. Belov, Professor, Director of Engineering Center “Casting Technologies and Materials”, e-mail: nikolay-belov@yandex.ru
S. O. Beltyukova, Engineer, Casting Process Technology Chair

Abstract

The Thermo-Calc program was used for the quantitative analysis of phase diagrams of ternary Al – Ti – X systems (where Х is Nb, Mo, Cr, V, Zr, W, Mn and Si) in the area of gamma-phase alloys on the basis of titanium aluminide TiAl. Isothermal and polythermal cross-sections were calculated together with temperatures of liquidus, solidus and other phase transformations. Isothermal cuts were calculated for the temperatures of 1200 and 800 °C. The first temperature is typical for hot isostatic pressing, and the second one corresponds to the blade operating temperatures. Polythermal cuts were calculated for the concentration of 45% (mol.) of Al, which corresponds to the average content in the well-known gamma-phase alloys. The critical temperatures and phase composition of selected alloys were calculated with this aluminium concentration. The calculation of Al – Ti – X systems in the given ranges has shown the
presence of the following phases:
α — solid solution on the basis of hexagonal close-packed lattice (α-titanium);
β — solid solution on the basis of BCC lattice (β-titanium);
β2 — solid solution on the basis of BCC lattice (with increased content of β-stabilizer);
γ — solid solution on the basis of TiAl aluminide;
α2 — solid solution on the basis of Ti3Al aluminide;
Ti5Si3 — titanium silicide;
σ — phase on the basis of AlX3 compound;
λ — phase on the basis of TiX2 compound (Laves phase).
There were defined the parameters of nonvariant eutectoid reaction α→α2+γ+β. According to the calculation, this reaction should proceed in the systems with niobium, molybdenum, chromium, tungsten and manganese. Temperature of this reaction is varied from 1095 °C (in the system Al – Ti – W) to 1036 °С (in Al – Ti – Mn system). There is shown that the phase composition of ternary alloys (including mass fractions of various phases (α, β, γ, α2, etc.)) and their element concentration (Ti, Al, Х) depend mostly on the heat treatment temperature.
This work was carried out with the support of the Grant of Russian Science Foundation 14-19-01033.

keywords Phase diagrams, titanium aluminides, gamma-phase alloys, isothermal cuts, polythermal cuts, crystallization range, unbalanced crystallization, eutectoid reaction
References

1. Ilin A. A., Kolachev B. A., Polkin I. S. Titanovye splavy. Sostav, struktura, svoystva (Titanium alloys. Composition, structure, properties). Moscow : All-Russian Institute of Light Alloys — Russian State Technological University, 2009. 520 p.
2. Appel F., Paul J. D. H., Oehring M. Gamma Titanium Aluminide Alloys: Science and Technology. Weinheim : Wiley-VCH Verlag & Co. KGaA, 2011. 745 р.
3. Xinhua Wu. Review of alloy and process development of TiAl alloys. Intermetallics. 2006. Vol. 14, iss. 10–11. pp. 1114–1122.
4. Joaquim Barbosa, C. Silva Ribeiro, A. Caetano Monteiro. Influence of superheating on casting of -TiAl. Intermetallics. 2007. Vol. 15, iss. 7. pp. 945–955.
5. Kuang J. P., Harding R. A., Campbell J. Microstructures and properties of investment castings of -titanium aluminide. Materials Science and Engineering A. 2002. Vol. 329–331. pp. 31–37.
6. Hu D., Wu X., Loretto M. H. Advances in optimization of mechanical properties in cast TiAl alloys. Intermetallics. 2005. Vol. 13, iss. 9. pp. 914–919.
7. Güther V., Rothe C., Winter S., Clemens H. Metallurgy, Microstructure and Properties of Intermetallic TiAl Ingots. BHM. 2010. Vol. 155, iss. 7. pp. 325–329.
8. Simpkins R. J., Rourke M. P., Bieler T. A., McQuayb P. A. The effects of HIP pore closure and age hardening on primary creep and tensile property variations in a TiAl XD™ alloy with 0.1 wt.% carbon. Materials Science and Engineering A. 2007. Vol. 463, iss. 1–2. pp. 208–215.
9. Huang Z. W., Voice W., Bowen P. Thermal exposure induced α2+γ→B2(ω) and α2→B2(ω) phase transformations in a high Nb fully lamellar TiAl alloy. Scripta Materialia. 2003. Vol. 48, iss. 1. pp. 79–84.
10. Belov N. A., Belov V. D., Alabin A. A., Petrovskiy P. V., Pavlinich S. P., Alikin P. V. Sposob termoobrabotki otlivok iz splavov na osnove gamma alyuminida titana (Method of heat treatment of casts made of alloys based on gamma titanium aluminide). Patent RF, No. 2502824 RF, IPC C 22 F 1/18. Applier and patent-holder: National University of Science and Technology “MISiS”. Applied: November 13, 2012. Published: December 27, 2013. Byulletin No. 36.
11. Witusiewicz V. T., Bondar A. A., Hecht U., Velikanova T. Ya. The Al – B – Nb – Ti system: IV. Experimental study and thermodynamic re-evaluation of the binary Al – Nb and ternary Al – Nb – Ti systems. Journal of Alloys and Compounds. 2009. Vol. 472, iss. 1–2. pp. 133–161.
12. Hao Y. L., Yang R., Cui Y. Y., Li D. The influence of alloying on the α2/(α2+γ)/γ phase boundaries in TiAl based systems. Acta materialia. 2000. Vol. 48, iss. 6. pp. 1313–1324.
13. Kainuma R., Fujita Y., Mitsui H., Ohnuma I., Ishida K. Phase equilibria among α(hcp), β(bcc) and γ(L10) phases in Ti – Al base ternary alloys. Intermetallics. 2000. Vol. 8, iss. 8. pp. 855–867.
14. Belov N. A., Chupakhin I. S. Kolichestvennyy analiz fazovogo sostava splava TNM-B1 na osnove alyuminida titana TiAl(γ) (Quantitative analysis of phase composition of TNM-B1 alloy on the basis of titanium aluminide TiAl(γ)). Metallovedenie i termicheskaya obrabotka metallov = Metal science and heat treatment. 2013. No. 9. pp. 32–37.
15. Fizicheskoe materialovedenie. V trekh tomakh. Tom 2. Fazovye prevrashcheniya v metallakh i splavakh i splavy s osobymi fizicheskimi svoystvami (Physical metallurgy. In three volumes. Volume 2. Phase transformations in metals and alloys with special physical properties). Under the editorship of R. W. Cahn and P. Haasen. Translated from English. Moscow : Metallurgiya, 1987. 624 p.
16. Belov N. A. Diagrammy sostoyaniya troynykh i chetvernykh sistem : uchebnoe posobie dlya vuzov (State diagrams of ternary and tetradic systems : tutorial for universities). Moscow : MISiS, 2007. 360 p.
17. Belov N. A., Samoshina M. E. Vliyanie temperatury GIP-obrabotki na fazovyy sostav liteynykh splavov na osnove gamma-alyuminida titana (Influence of temperatures of HIP-treatment on phase composition of cast
alloys on the basis of gamma-aluminide of titanium). Izvestiya vuzov. Tsvetnaya metallurgiya = Russian Journal of Non-Ferrous Metals. 2013. No. 6. pp. 27–35.
18. Novikov I. I. Goryachelomkost tsvetnykh metallov i splavov (Hot-shortness of non-ferrous metals and alloys). Moscow : Nauka, 1966. 299 p.

Language of full-text russian
Full content Buy
Back