Isothermal oxidation of TiAl alloy

Reddy, Ramana G.; Wen, Xiaoli; Mantha, D.

doi:10.1007/s11661-001-0209-4

Cited by 41 publications

(22 citation statements)

References 10 publications

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“…It might be a possible replacement for traditional Ni-based superalloy components in aircraft turbine engines. However, the oxidation resistance of c-TiAl or c-TiAl based alloys is unsatisfied for practical applications at temperatures above 800°C [1,2]. The insufficient oxidation resistance is attributed to the formation of loose oxide scales of TiO 2 and Al 2 O 3 other than a dense continuous Al 2 O 3 scale [2][3][4] on their surfaces as exposed in hot air.…”

Section: Introductionmentioning

confidence: 99%

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Formation kinetics of multi-layered interfacial zone between γ-TiAl and glass–ceramic coatings via interfacial reactions at 1000°C

2015

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Section: Introductionmentioning

confidence: 99%

“…It is known that c-TiAl forms loose oxide scales which are composed of mixed TiO 2 and Al 2 O 3 as exposed in hot air[1,2]. Spallation of the scales was always accompanied during oxidation.…”

mentioning

confidence: 99%

Formation kinetics of multi-layered interfacial zone between γ-TiAl and glass–ceramic coatings via interfacial reactions at 1000°C

2015

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“…Experimental determination of self-diffusivity is easier and can be related to the interdiffusion coefficient by a thermodynamic factor F, as given in Eq. [6]:…”

Section: Diffusion Analysismentioning

confidence: 99%

“…It is well known that TiAl 3 favors the formation of a continuous a-Al 2 O 3 protective scale, while TiAl has lower activation energy for the oxidation and Ti 3 Al has very poor oxidation resistance at high temperatures. [4][5][6] Although TiAl 3 forms an alumina layer on oxidation, the brittle nature of the oxide layer owing to the mismatch of thermal expansion coefficients between the base alloy and the oxide has led to the research on oxidation resistance of Ti 3 Al intermetallic phase for high-temperature applications. In addition, Ti 3 Al has the highest solubility of oxygen, [7] which also stabilizes the a 2 phase.…”

Section: Introductionmentioning

confidence: 99%

Oxidation and Diffusion in Ti-Al-(Mo, Nb) Intermetallics

Ramachandran

Mantha

Williams

et al. 2010

Metall Mater Trans A

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The oxidation resistance of Ti-Al intermetallics is superior to many of their counterparts at high temperatures. High-temperature stability of these intermetallics appears to improve with a ternary alloying addition such as Mo, Nb, etc. A detailed analysis of oxidation of the Ti 3 Al intermetallics, Ti 3 Al-2.9 at. pct Mo and Ti 3 Al-1.1 at. pct Nb, in pure oxygen using crystallographic and microscopic techniques is presented here. The alloy containing 1.1 at. pct Nb did not show an improvement in oxidation resistance over the base alloy but that containing 2.9 at. pct Mo showed marked resistance to oxidation. Activation energies of oxidation for both the alloys were comparable with those reported in the literature for similar compositions. TiO 2 and Al 2 O 3 were the major phases present in the oxide scales of the oxidized alloys. The crystal orientations from the X-ray diffraction (XRD) patterns and the morphologies from scanning electron microscopy (SEM) were in good agreement and were helpful in further analysis of the oxidation process. The effective diffusion of oxygen in the oxide layers was calculated using the mole fraction of individual oxide and the diffusivity of oxygen in pure oxide. The activation energy for the effective diffusion of oxygen through the oxide layers was determined to bẽ 24 kJ/mol. The activation energy for the oxidation process was higher than that of the diffusion of oxygen. Hence, it can be concluded that the oxidation process in both the alloys studied is not diffusion controlled.

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“…The activation-energy values for the 9Nb2Ta, 11Nb2Ta, 9Nb2Zr, and 11Nb2Zr alloys have been found to be 348, 346, 750, and 560 kJ/mole, respectively. Table II compares the Q values found in the literature [16][17][18][19] with the Unnam et al [16] Ti-26Al 255 Welsch et al [18] Ti-32Al 299…”

Section: Rate-constant and Activation-energy Calculationsmentioning

confidence: 99%

Oxidation behavior and transmission electron microscope characterization of Ti-44Al-x Nb-2(Ta,Zr) alloys

Woo

Varma

Mahapatra³

2003

Metall Mater Trans A

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Quaternary additions of 2 at. pct of Ta or Zr were made to the ternary Ti-44Al-xNb (X ϭ 9 and 11) alloys to study the oxidation behavior at 900°C, 950°C, and 1000°C for a period of 1 week. The Ta addition improves the oxidation resistance, while it is degraded by Zr compared to the ternary alloys. Identification of the oxides formed in the scale has been characterized by energydispersive atomic X-ray (EDAX) in a scanning electron microscope (SEM). The transmission electron microscope (TEM) analysis of the microstructures developed during oxidation has been compared with Ti-44Al-xNb alloys in order to determine the influence of quaternary additions of Ta and Zr on the phase transformations taking place during the extended period of heating. The formation of spotty ␣ 2 in the isolated ␥ grains appears to be associated with the inferior oxidation resistance of xNb2Zr alloys.

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Isothermal oxidation of TiAl alloy

Cited by 41 publications

References 10 publications

Formation kinetics of multi-layered interfacial zone between γ-TiAl and glass–ceramic coatings via interfacial reactions at 1000°C

Formation kinetics of multi-layered interfacial zone between γ-TiAl and glass–ceramic coatings via interfacial reactions at 1000°C

Oxidation and Diffusion in Ti-Al-(Mo, Nb) Intermetallics

Oxidation behavior and transmission electron microscope characterization of Ti-44Al-x Nb-2(Ta,Zr) alloys

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