Effect of oxygen on the microstructure of annealed TiAl based alloy

• Autorzy: Klimova A. , Lapin J.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The aim of the present work was to investigate the effect of oxygen on the microstructure and Vickers hardness after annealing followed by free air cooling of cast Ti-48Al-2Nb-1Cr-0.2Si (at.%) alloy. Design/methodology/approach: The effect of oxygen on the microstructure of cast intermetallic TiAl-based alloy with nominal composition Ti-48Al-2Nb-1Cr-0.2Si (at.%) was studied after isothermal annealing at temperatures ranging from 1150 to 1320°C followed by free air cooling to room temperature. The samples for annealing were prepared from an ingot with an oxygen content of 400 wt. ppm and from cast turbocharger wheels with two different amounts of oxygen of 1000 and 1800 wt. ppm. Findings: While the microstructure of the alloy with the oxygen content of 400 wt. ppm changes from duplex one composed of lamellar α2+γand single phase γgrains to nearly lamellar with increasing annealing temperature, the microstructure of the annealed samples with oxygen content of 1000 and 1800 wt. ppm remains nearly lamellar within the studied temperature range. Research limitations/implications: The evolution of the Vickers hardness with the annealing temperature is discussed from the point of view of volume fraction of single phase γgrains. The effect of oxygen on the Vickers hardness of studied castings is described. Originality/value: The alloy was studied in the form of cast ingot and centrifugally cast turbocharger wheels with different amounts of oxygen. Alloying with Cr and Nb was selected for better ductility and oxidation resistance of the studied alloy.

Słowa kluczowe

EN

oxygen; heat treatment; microstructure; hardness

PL

tlen; obróbka cieplna; mikrostruktura; twardość

• Wydawca: International OCSCO World Press
• Czasopismo: Archives of Materials Science and Engineering
• Rocznik: 2014
• Tom: Vol. 70, nr 1
• Strony: 21--27
• Opis fizyczny: Bibliogr. 9 poz.

Twórcy

autor

Klimova A.

• Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3, Slovak Republic

autor

Lapin J.

• Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Račianska 75, 831 02 Bratislava 3, Slovak Republic

Bibliografia

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• [2] J. Lapin, Z. Gabalcová, T. Pelachová, Effect of Y2O3 crucible on contamination of directionally solidified intermetallic Ti-46Al-8Nb alloy, Intermetallics 19 (2011) 396-403.
• [3] J. Lapin, L'. Ondrúš, M. Nazmy, Directional solidification of intermetallic Ti-46Al-2W-0.5Si alloy in alumina moulds, Intermetallics 10 (2002) 1019-1031.
• [4] T. Tetsui, T. Kobayashi, T. Ueno, H. Harada, Consideration of the influence of contamination from oxide crucibles on TiAl cast material, and the possibility of achieving low-purity TiAl precision cast turbine wheels, Intermetallics 31 (2012) 274-281.
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• [6] M. Lamirand, J.L. Bonnentien, S. Guérin, G. Ferrière, J.P. Chevalier, Relative effects of chromium and niobium on microstructure and mechanical properties as a function of oxygen content in TiAl alloys, Scripta Materialia 56 (2007) 325-328.
• [7] B. Lu, L. Huang, Y. Liu, X. Liang, B. Liu, Y. He, H. Li, Evolution of lamellar structure in Ti-47Al-2Nb-2Cr-0.2W alloy sheet, Transactions of Non-ferrous Metals Society of China 23 (2013) 1293-1298.
• [8] A. Klimová, J. Lapin, Microstructure evolution during annealing of cast tial-based alloy, METAL 2014: 23rdInternational Conference on Metallurgy and Materials, 21-23.05.2014. Brno, Czech Republic, CD-ROM. Ostrava: TANGER Ltd., 2014.
• [9] A. Menand, A. Huguet, A. Nérac-Partaix, Interstitial solubility in γ and α2 phases of TiAl-based alloys, Acta Materialia 44/12 (1996) 4729-4737.