Influence of Moisture on the Oxidation of γ‐TiAl

Kremer, Raimar; Auer, W.

doi:10.1002/9783527612413.ch20

Cited by 2 publications

(2 citation statements)

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“…Therefore the oxide formation should be suppressed. However, investigations of Kremer and Auer revealed poor oxidation behaviour of g-TiAl in water vapour containing atmosphere caused by enhanced Al 2 O 3 growth [20]. These results are in good agreement with the present findings on enhanced oxidation in hydrogen containing atmosphere.…”

supporting

confidence: 93%

Influence of different annealing processes under various atmospheres on the oxidation behaviour of γ-TiAl

Ebach-Stahl

Fröhlich

Leyens

2009

Materials at High Temperatures

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A detailed study of the oxidation behaviour of bare g-TiAl based alloy Ti-45Al-8Nb under various conditions, such as different atmospheres, pressures, temperatures (900 C, 1000 C) and times (100-200 h) is presented. Under high vacuum conditions (10 À 6 mbar) a continuous zone of a 2-Ti 3 Al was formed at the surface with an oxygen-enriched phase on top. No oxide scale formation was obvious. During thermal treatment under Ar-atmosphere at low vacuum pressure (approximately 50 mbar) mainly nitrides (TiN, Ti 2 AlN) and Al 2 O 3 particles were formed at the surface with an a 2-layer below. Annealing g-TiAl in hydrogen atmosphere (about 1040 mbar) led to the formation of a thick reaction zone. A TiO 2 layer was formed on top, followed by a mixed oxide scale. Beneath that scale a thick region with alumina, s-Nb 2 Al and a 2-Ti 3 Al was observed. Moreover, the oxidation behaviour of several thermally pre-treated samples was tested by cyclic oxidation at 900 C in air. The microstructure of the oxide scale formed after testing can be compared with that of non pre-treated material. g-TiAl annealed under high vacuum conditions exhibits the lowest oxidation rate, while the mass gain of specimens pre-treated under Ar-atmosphere increased rapidly in the first cycles. All pre-treated specimens exceeded a lifetime of 600 cycles at minimum. The reference material failed after 520 cycles.

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confidence: 93%

Influence of different annealing processes under various atmospheres on the oxidation behaviour of γ-TiAl

Ebach-Stahl

Fröhlich

Leyens

2009

Materials at High Temperatures

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“…It should be mentioned that the oxidation curves from reference 17 was obtained from TGA tests in relatively dry (80%N 2 þ 20%O 2 ) air, while oxidation tests in this study was conducted in laboratory air. It is known that the weight gain will be more severe in the atmosphere which has more oxygen [28]. Although it is hard to directly compare the oxidation behavior between TiAle2Nbe2Mo alloy and other alloys, TiAle2Nbe2Mo alloy show moderate oxidation behavior compared to other alloys at both 800 C and 900 C. The stable oxidation behavior is well maintained for up to 500 h while data for most of the other studies are only available up to 150 h. It is generally known that the oxidation behavior of TiAl alloys in oxygen or air in the temperature range from 800 C to 1150 C closely follows parabolic kinetics [18].…”

Section: Elemental Distributions On the Cross Sectionmentioning

confidence: 99%