TiAl3 formation by furnace annealing of Ti/Al bilayers and the effect of impurities

Zhao, X.-A.; So, F. C. T.; Nicolet, M.‐A.

doi:10.1063/1.340981

Cited by 36 publications

(14 citation statements)

References 20 publications

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“…Similar behavior has been attributed to the formation of pores during the synthesis of various aluminides from powder mixtures [31][32][33][34][35][36]. This is also in agreement with studies suggesting that the diffusion of aluminum atoms into titanium particles is the predominant mechanism governing the formation of titanium aluminides [21,22,[25][26][27]. The globular morphology of the TiAl 3 phase obtained in this study is quite similar to what Xu et al [29] observed for the TiAl 3 phase in diffusion couple experiments.…”

Section: Tisupporting

confidence: 93%

“…This observation has been explained on the basis of the higher diffusivity of aluminum ions in TiAl 3 in comparison with other aluminides, which in any case might be formed in small amounts [23]. Formation of TiAl 3 on the titanium side of the diffusion couple, together with the movement of markers, proved that aluminum is the dominant diffusing specie [4,21,22,[25][26][27]. However, diffusion of titanium has also been reported by some workers [28,29].…”

Section: Introductionmentioning

confidence: 58%

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Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Sina

Iyengar

2015

J Therm Anal Calorim

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The formation of titanium aluminides in Ti-Al elemental powder mixtures containing 25, 50 and 75 at.% Al, has been studied using differential scanning calorimetry (DSC). Phase evolution in the mixture was followed by heating the compacted samples up to 1273 K at 7.5 and 15 K min -1 . The cooled samples were characterized using X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy. The results showed that the primary combustion product in all the samples was TiAl 3 , and the combustion reaction occurred below the melting point of aluminum only in Ti-rich samples. In Alrich samples (75 at.% Al), TiAl 3 was obtained as a porous, single-phase product after combustion. In samples containing 25 and 50 at.% Al, the combustion reaction was incomplete and the unreacted titanium particles were covered by a layer of TiAl 3 . In these samples, other intermetallic compounds such as TiAl 2 , TiAl and Ti 3 Al were observed to form upon heating beyond the combustion peak and are attributed to the solid-state reaction between unreacted titanium and TiAl 3 . Heating the samples with 25 at.% Al to 1273 K for an hour led to the formation of a homogenous Ti 3 Al product, while a multiphase product with a dominant TiAl phase was observed in samples containing 50 at.% Al. Calculations based on DSC data show that the formation of TiAl 3 through the reaction between solid titanium and molten aluminum is associated with an apparent activation energy of 195 ± 20 kJ mol -1 and an enthalpy of -114 ± 5 kJ mol -1 .

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Section: Tisupporting

confidence: 93%

Section: Introductionmentioning

confidence: 58%

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Sina

Iyengar

2015

J Therm Anal Calorim

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“…From Table 3, the Q k values of TiAl 2 and -TiAl phases formation in this study are very similar in magnitude with those of the TiAl 3 phase in the Ti-Al thin film diffusion systems, [9][10][11][12] but are lower than those of Ti-Al product formation in Ti-Al bulk systems. [6][7][8] A possible explanation in Q k for this discrepancy could be that the intrinsic defects, voids and the residual stress inherent in the thin film are more than those in the bulk form.…”

Section: Interreaction Kinetics Of Phase Formation Betweenmentioning

confidence: 50%

“…Moreover, from many reported diffusion couples tests in the Ti-Al system, the TiAl 3 layer is observed to grow rapidly and complies with the parabolic time dependence. 6,[9][10][11][12] In our cases, we suggest that the TiAl 3 growth in Fig. 1 is also following the parabolic law, although its growth kinetics is not investigated in this study.…”

Section: Methodsmentioning

confidence: 88%

“…In addition, the growth of the TiAl 3 phase in the Ti-Al thin film couple system obeys the diffusion controlled kinetics with activation energies varying from about 150 to 190 kJ/mol according to different researchers. [9][10][11][12] To our best knowledge, most investigations on phase interreactions in the Ti-Al system have concentrated on the TiAl 3 formation of the thin film diffusion couple or the bulk diffusion couple. In the case of the diffusion couple of TiAl 3 thin film on -TiAl or on 2 -Ti 3 Al bulk alloys, their interreactions to form TiAl 2 andTiAl phases at high temperature have not previously been reported.…”

Section: Introductionmentioning

confidence: 99%

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Interreactions of TiAl3 Thin Film on Bulk γ-TiAl and on Bulk α2-Ti3Al Alloys at 700—1000°C

Chu

2004

Mater. Trans.

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Interreactions of diffusion couples of TiAl 3 film on bulk -TiAl and TiAl 3 film on bulk 2 -Ti 3 Al are investigated at high temperature. Experimental results show that TiAl 2 layer and TiAl 2 /-TiAl mixed layers are observed at the interfaces of TiAl 3 film/bulk -TiAl and TiAl 3 film/bulk 2 -Ti 3 Al diffusion couples, respectively, at 700$1000C. In addition, the growth rates of TiAl 2 and -TiAl product layers comply well with a parabolic law. The growth activation energy, Q k , of the TiAl 2 phase in the TiAl 3 film/bulk -TiAl system is calculated as 158.9 kJ/ mol, and Q k values of -TiAl and TiAl 2 phases in TiAl 3 film/bulk 2 -Ti 3 Al system are 163.4 kJ/mol and 147.9 kJ/mol, respectively. These Q k values are similar in magnitude with those of TiAl 3 phase formation in Ti-Al thin film diffusion systems. In this study, TiAl 2 formation is suggested to have been nucleated at the interface during the heating prior to reaching the set temperature.

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Formation processes of the surface oxidized layer on Al-Ti alloy films

Murakami

Takeyama

Noya

2000

Electron. Comm. Jpn. Pt. II

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Characterization and formation process of the surface oxidized layer formed on the surface of Al‐Ti alloy thin films are examined with respect to the alloy composition and alloy film structure. While Al atoms within the alloy films form a thin surface Al2O3 layer by preferential oxidation in the initial stage of oxidation regardless of the alloy composition or its structure, for the case of a sufficiently Al‐rich alloy composition, a surface Al2O3 layer comparable to that formed on the Al surface is formed, in which Ti atoms in the alloy can exist beneath the Al‐oxide layer in the metal state, and the surface oxide layer protects the alloy film from further oxidation even after the oxidation treatment at 300 °C for 1 h. On the other hand, for a Ti‐rich alloy composition that cannot guarantee the preferential oxidation of the Al surface, the oxidation of Ti occurs due to the oxygen atoms introduced through a thin Al2O3 as well as the associated oxidation of Al, the oxidation easily progresses inside the alloy. It has been found that even for Al‐Ti alloys with approximately the same composition, the oxide layer thickness is different between the metal compound film and the amorphous alloy film. It is found that the oxide layer formed on the compound film is thinner. This is attributed to the difference in the interaction as a chemical bonding inherent in the alloy structure between the compound phase and the amorphous phase during the ionization process of metal as a reaction species. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(8): 58–66, 2000

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TiAl3 formation by furnace annealing of Ti/Al bilayers and the effect of impurities

Cited by 36 publications

References 20 publications

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Interreactions of TiAl<SUB>3</SUB> Thin Film on Bulk γ-TiAl and on Bulk α<SUB>2</SUB>-Ti<SUB>3</SUB>Al Alloys at 700—1000°C

Formation processes of the surface oxidized layer on Al-Ti alloy films

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TiAl3 formation by furnace annealing of Ti/Al bilayers and the effect of impurities

Cited by 36 publications

References 20 publications

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Reactive synthesis and characterization of titanium aluminides produced from elemental powder mixtures

Interreactions of TiAl<SUB>3</SUB> Thin Film on Bulk &gamma;-TiAl and on Bulk &alpha;<SUB>2</SUB>-Ti<SUB>3</SUB>Al Alloys at 700&mdash;1000&deg;C

Formation processes of the surface oxidized layer on Al-Ti alloy films

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Interreactions of TiAl<SUB>3</SUB> Thin Film on Bulk γ-TiAl and on Bulk α<SUB>2</SUB>-Ti<SUB>3</SUB>Al Alloys at 700—1000°C