Interstitial solubility in γ and α2 phases of TiAl-based alloys

Menand, A.; Huguet, Arnaud; Nérac-Partaix, A.

doi:10.1016/s1359-6454(96)00111-5

Cited by 220 publications

(107 citation statements)

References 12 publications

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“…However, this correlation is valid only for the lamellar a 2 þ g microconstituent hardness, because on the g constituent hardness was found to be almost constant all over the samples. This fact confirms Menand findings [3], suggesting that oxygen dissolves preferentially on a 2 phase and reveal a direct relation between these two parameters. Fig.…”

Section: Resultssupporting

confidence: 90%

Effect of low level contamination on TiAl alloys studied by SIMS

Teodoro

Barbosa

Naia

et al. 2004

Applied Surface Science

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Titanium aluminides are a valuable alternative to superalloys in applications where the ratio resistance/density is important. Since the ordinary production routes lead to high final costs, an alternative might be the use of traditional casting techniques by induction melting of the alloy in a ceramic crucible and pouring into ceramic moulds, made by the investment casting process. However, due to the high reactivity of Ti alloys, the use of traditional ceramic materials cannot be used, as they lead to oxide formation and oxygen pick up from both the crucible and the moulding materials.In this work, the effect of low level contamination was studied by SIMS. Special attention was given to the oxygen concentration for samples obtained with different mould materials. The comparison of SIMS in-depth profiles with hardness profiles, gives insight concerning the significance of the oxygen concentration in the properties of the alloy and regarding the choice of the most suitable materials for TiAl production. #

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Section: Resultssupporting

confidence: 90%

Effect of low level contamination on TiAl alloys studied by SIMS

Teodoro

Barbosa

Naia

et al. 2004

Applied Surface Science

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“…The partitioning of oxygen was observed to be the most pronounced, as reported elsewhere [12,23,24]. Oxygen prefers the α 2 -phase to the γ -phase by a ratio of almost 14:1.…”

Section: Elemental Partitioningsupporting

confidence: 82%

“…The oxygen concentration in the γ -phase of our alloy is more than twice the oxygen concentration detected in the γ -phase of binary TiAl alloys [24], most likely due to the presence of seven additional micro-alloying elements in our alloy.…”

Section: Discussionmentioning

confidence: 66%

“…Our analyses show that the oxygen concentration reaches 0.09 at.% in the γ -phase and 1.24 at.% in the α 2 -phase. This is inconsistent, however, with Menand et al's suggested maximum oxygen concentration of 0.025 at.% in the γ -phase [24]. Menand et al's thorough study of oxygen concentrations in a Ti 54 Al 46 alloy suggests that the multi-component nature of our alloy can have a significant effect on the maximum concentration of oxygen dissolved in the γ -phase.…”

Section: Elemental Partitioningmentioning

confidence: 69%

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Atomic Scale Chemistry of α₂/ Interfaces in a Multi-Component TiAl Alloy

2004

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Abstract. We report on the distribution of micro-alloying elements in a multi-component TiAl-based alloy. The specimen contains 3 at.% Nb, 1.5 at.% Cr, 0.5 at.% Mn, 0.6 at.% (W + Hf + Zr), and 0.2 at.% each of B, C, and O. The distributions of all micro-alloying elements with respect to the heterophase interface between α 2 and γ lamellae are analyzed with a three-dimensional atom-probe (3DAP) microscope. All the elements partition except boron, which resides primarily in boride precipitates. Oxygen, C, Mn, and Cr partition to the α 2 -phase, whereas Nb and Zr partition to the γ -phase. Both W and Hf exhibit excess concentration values within ca. 7 nm of the lamellar interface in the α 2 -phase, and their near interfacial excesses are 0.26 and 0.35 atoms nm -2 , respectively.

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“…As reported previously, 19) the concentration of internal oxygen of the EPM TiAl alloys was reduced by additions of yttrium and the oxides of Y 2 O 3 precipitated by the reaction of yttrium with the internal oxygen which was introduced during EPM processing of the experimental alloys. Because there is strong binding between yttrium and oxygen atoms, 30) and because the average oxygen concentration of EPM experimental alloys is 1500 mass ppm, which is about ten times higher than the solubility limit of 128 mass ppm, 31) supersaturated oxygen is prone to react with yttrium to form the Y 2 O 3 particles.…”

Section: Methodsmentioning

confidence: 99%

High-Temperature Oxidation Behavior of Elemental Powder Metallurgy Processed TiAl-Mn-Mo-C Alloys with Yttrium Addition

Hwang

Umakoshi

2004

Mater. Trans.

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Effects of yttrium addition on the formation of oxide scales and the oxidation resistance of elemental powder metallurgy (EPM) processed TiAl-Mn-Mo-C alloys were studied. The Y-containing TiAl-based alloys (0:1$0:6 at%Y) showed better oxidation resistance than Y-free alloy oxidized in air at 800C for 350 h. The Y-containing alloys showed a significantly reduced weight gain, especially for 0.6 at%Y-added alloy. In the Y-free alloy, the scale formed during extended air-exposure at 800 C consisted of TiO 2 and -Al 2 O 3 . For 0.6 at%Y-added alloy, however, the oxide scale was composed of a complex mixture of TiO 2 , -Al 2 O 3 , Y 2 O 3 and Al 5 Y 3 O 12 . The formation of multi-phase (Y, Al)O-type oxides layer in a transitional Y-rich subscale close to the substrate and an increase of the amount of -Al 2 O 3 in the mixture oxide layer in the Y-added alloys were the main contributor to improving the oxidation resistance of the alloys. The reduction of oxygen content in the substrate also had a beneficial effect on the oxidation resistance of the Y-containing TiAl-based alloys.

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Interstitial solubility in γ and α2 phases of TiAl-based alloys

Cited by 220 publications

References 12 publications

Effect of low level contamination on TiAl alloys studied by SIMS

Effect of low level contamination on TiAl alloys studied by SIMS

Atomic Scale Chemistry of α₂/ Interfaces in a Multi-Component TiAl Alloy

High-Temperature Oxidation Behavior of Elemental Powder Metallurgy Processed TiAl-Mn-Mo-C Alloys with Yttrium Addition

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Interstitial solubility in γ and α2 phases of TiAl-based alloys

Cited by 220 publications

References 12 publications

Effect of low level contamination on TiAl alloys studied by SIMS

Effect of low level contamination on TiAl alloys studied by SIMS

Atomic Scale Chemistry of α2/ Interfaces in a Multi-Component TiAl Alloy

High-Temperature Oxidation Behavior of Elemental Powder Metallurgy Processed TiAl-Mn-Mo-C Alloys with Yttrium Addition

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Atomic Scale Chemistry of α₂/ Interfaces in a Multi-Component TiAl Alloy