Microstructural evolution and high-temperature oxidation mechanisms of a titanium aluminide based alloy

Qu, Shoujiang; Shougao, Tang; Ai, Feng; Feng, Cong; Shen, Jun; Chen, D.L.

doi:10.1016/j.actamat.2018.02.013

Cited by 133 publications

(28 citation statements)

References 57 publications

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“…It is sandwiched between the complete and residual O-Ti 2 AlNb laths, which corresponds to the former position of the B2 phase. AlNb 2 is considered as a by-product during the oxidation of the Nb-containing TiAl-based alloy, which is due to the reaction of enriched Nb and Al elements 45 . There are a large number of Nb element in the B2 phase 43 .…”

Section: Discussionmentioning

confidence: 99%

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Thermodynamic and microstructural study of Ti2AlNb oxides at 800 °C

Xiang

et al. 2018

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The high-temperature structural applications of Ti2AlNb-based alloys, such as in jet engines and gas turbines, inevitably require oxidation resistance. The objective of this study is to seek fundamental insight into the oxidation behavior of a Ti2AlNb-based alloy via detailed microstructural characterization of oxide scale and scale/substrate interface after oxidation at 800 °C using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM). The oxide scale exhibits a complex multi-layered structure consisting of (Al,Nb)-rich mixed oxide layer (I)/mixed oxide layer (II)/oxygen-rich layer (III)/substrate from the outside to inside, where the substrate is mainly composed of B2 and O-Ti2AlNb phases. High-resolution TEM examinations along with high-angle annular dark-field (HAADF) imaging reveal: (1) the co-existence of two types (α and δ) of Al2O3 oxides in the outer scale, (2) the presence of metastable oxide products of TiO and Nb2O5, (3) an amorphous region near the scale/substrate interface including the formation of AlNb2, and (4) O-Ti2AlNb phase oxidized to form Nb2O5, TiO2 and Al2O3.

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Section: Discussionmentioning

confidence: 99%

“…4(b) . AlNb 2 is stably present at the interface, indicating that its oxidation resistance is relatively strong 45 , however, the discontinuous nature of AlNb 2 at the interface makes the effect limited.…”

Section: Discussionmentioning

confidence: 99%

Thermodynamic and microstructural study of Ti2AlNb oxides at 800 °C

Xiang

et al. 2018

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“…The weight of samples increases with the extension of oxidation time, and all trends exhibit parabolic behavior [51]. The weight gain rate of the MoSi 2 (Cr 5 Si 3 )-RSiC composites is much lower than that of RSiC, indicating that the composites possess improved oxidation resistance [51]. This improvement is mainly attributed to the acute decrease in porosity of RSiC and the outstanding oxidation resistance of the infiltrated phases [2].…”

Section: Oxidation Behavior Of the Mosi 2 (Cr 5 Si 3 )-Rsic Compositementioning

confidence: 98%

“…4. The weight of samples increases with the extension of oxidation time, and all trends exhibit parabolic behavior [51]. The weight gain rate of the MoSi 2 (Cr 5 Si 3 )-RSiC composites is much lower than that of RSiC, indicating that the composites possess improved oxidation resistance [51].…”

Section: Oxidation Behavior Of the Mosi 2 (Cr 5 Si 3 )-Rsic Compositementioning

confidence: 99%

High temperature mechanical retention characteristics and oxidation behaviors of the MoSi2(Cr5Si3)—RSiC composites prepared via a PIP—AAMI combined process

et al. 2019

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In the present paper, MoSi 2 (Cr 5 Si 3)-RSiC composites were prepared via a combination of precursor impregnation pyrolysis (PIP) and MoSi 2 −Si−Cr alloy active melt infiltration (AAMI) process. Composition, microstructure, mechanical retention characteristics, and oxidation behaviors of the composites at elevated temperature were studied. X-ray diffraction (XRD) pattern confirms that the composites mainly compose of 6H-SiC, hexagonal MoSi 2 , and tetragonal Cr 5 Si 3. Scanning electron microscopy (SEM) image reveals that nearly dense MoSi 2 (Cr 5 Si 3)-RSiC composites exhibiting three-dimensionally (3D) interpenetrated network structure are obtained when infiltrated at 2173 K, and the interface combination of the composites mainly depends on the composition ratio of infiltrated phases. Oxidation weight gain rate of the composites is much lower than that of RSiC matrix, where MoSiCr2 possesses the lowest value of 0.1630 mg⋅cm −2 , about 78% lower than that of RSiC after oxidation at 1773 K for 100 h. Also, it possesses the highest mechanical values of 139.54 MPa (flexural strength σ f and RT) and 276.77 GPa (elastic modulus E f and RT), improvement of 73.73% and 29.77% as compared with that of RSiC, respectively. Mechanical properties of the composites increase first and then decrease with the extension of oxidation time at 1773 K, due to the cooperation effect of surface defect reduction via oxidation reaction and thermal stress relaxation in the composites, crystal growth, and thickness increase of the oxide film. Fracture toughness of MoSiCr2 reaches 2.24 MPa•m 1/2 (1673 K), showing the highest improvement of 31.70% as compared to the RT value.

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“…Quando comparadas com as outras ligas, os aluminetos de titânio (TiAl) se revelam promissores para aplicações estruturais em substituição às superligas de Ni [4][5][6][7] , visto que apresentam principalmente, alto ponto de fusão (1400 -1500 °C), manutenção de elevados níveis de resistência mecânica em condições de temperaturas entre 600 e 950°C , e além disso, seu maior diferencial consiste na baixa densidade (3,8 -4,0 mg / cm 2 ), que resulta em uma redução de até 50% em massa dos componentes fabricados a partir desta liga [1,2,[8][9][10][11] .…”

Section: Introductionunclassified

Caracterização microestrutural e comportamento à oxidação em temperaturas elevadas de ligas TiAl

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Microstructural evolution and high-temperature oxidation mechanisms of a titanium aluminide based alloy

Cited by 133 publications

References 57 publications

Thermodynamic and microstructural study of Ti2AlNb oxides at 800 °C

Thermodynamic and microstructural study of Ti2AlNb oxides at 800 °C

High temperature mechanical retention characteristics and oxidation behaviors of the MoSi2(Cr5Si3)—RSiC composites prepared via a PIP—AAMI combined process

Caracterização microestrutural e comportamento à oxidação em temperaturas elevadas de ligas TiAl

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