Resistance to High-Temperature Oxidation of Ti-Al-Nb Alloys

Małecka, J.

doi:10.3390/ma15062137

Cited by 6 publications

(3 citation statements)

References 38 publications

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“…Moreover, in the case of the irradiated samples, the decrease in their hardness was about 30-50% at temperatures of 900-1000 • C, which indicates the low stability of the irradiated samples to high-temperature degradation, as well as its acceleration due to accumulated structural distortions in the damaged layer. In this case, as shown in the study published by the authors of [37], accelerated degradation can be caused via the formation of oxide layers on the surface, which, in the case of a near-surface layer damaged by irradiation, can contribute to its accelerated degradation and peeling, which leads towards a sharp deterioration in hardness. As shown in the presented data, the Nb alloys, both in the original and irradiated states, proved to be the least resistant to high-temperature degradation.…”

Section: Evaluation Results Of the Studied Alloy Samples For Thermal ...mentioning

confidence: 92%

Effects of Structural Radiation Disorder in the Near-Surface Layer of Alloys Based on NbTiVZr Compounds Depending on the Variation of Alloy Components

Giniyatova,

Kadyrzhanov,

Shlimas

et al. 2023

Crystals

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This research investigated how changes in the composition of Nb–Ti–V–Zr-based alloys affect their resistance to radiation damage and the preservation of strength characteristics when exposed to the heavy ions Kr15+ and Xe23+. These heavy ions simulate the impact of nuclear fuel fission fragments on the material. The primary objective of this study was to explore how variations in alloy components influence radiation resistance and the retention of alloy strength properties. Accumulation of radiation defects can potentially lead to embrittlement and a decrease in resistance to external factors during operation. An analysis of the X-ray diffraction data obtained from the initial alloy samples, in relation to the variations in the number of components, revealed that an increase in the number of components leads to the formation of a denser crystal structure. Additionally, this resulted in the emergence of a dislocation strengthening factor associated with changes in crystallite size. Concurrently, when assessing changes in the strength characteristics of the irradiated alloys, it was observed that the NbTiV and NbTiVZr alloys demonstrated the highest resistance to strength property degradation, specifically a 2.5- to 5-fold increase in resistance against a significant decrease in hardness. It was confirmed that the significant factor contributing towards the enhancement and preservation of the structural and strength properties is the dislocation strengthening mechanism. An increase in dislocation strengthening effectively enhances resistance against destructive embrittlement, particularly when exposed to high-dose irradiation.

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Section: Evaluation Results Of the Studied Alloy Samples For Thermal ...mentioning

confidence: 92%

Effects of Structural Radiation Disorder in the Near-Surface Layer of Alloys Based on NbTiVZr Compounds Depending on the Variation of Alloy Components

Giniyatova,

Kadyrzhanov,

Shlimas

et al. 2023

Crystals

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“…Previous research [17][18][19][20][21][22][23][24][25][26][27] reveals that the addition of alloying elements, such as W, Mo, Ta and Nb, can prevent the lamella from coarsening and significantly improve the hightemperature oxidation resistance of the TiAl alloy; among these, the effects of Ta and Nb are particularly notable. Nb can efficiently improve the outward diffusion rate of Al while reducing the growth rate of TiO 2 particles and the diffusion rate of O [24,28,29].…”

Section: Introductionmentioning

confidence: 99%

Effects of Thermal Exposure on the Microstructure and Mechanical Properties of a Ti–48Al–3Nb–1.5Ta Alloy via Powder Hot Isostatic Pressing

Zuo,

Hu,

Wang

et al. 2024

Materials

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Research on how thermal exposure affects the microstructure and mechanical properties of the Ti–48Al–3Nb–1.5Ta (at. %) alloy, which is prepared via powder hot isostatic pressing (P–HIP), is essential since this low-density alloy shows promise for use in high-temperature applications, particularly for aero-engines, which require long-term stable service. In this study, a P–HIP Ti–48Al–3Nb–1.5Ta (at. %) alloy was exposed to high temperatures for long durations. The phase, microstructure and mechanical properties of the P–HIP Ti–48Al–3Nb–1.5Ta alloy after thermal exposure under different conditions were analyzed using XRD, SEM, EBSD, EPMA, TEM, nanomechanical testing and tensile testing. The surface scale is composed of oxides and nitrides, primarily Al2O3, TiO2, and TiN, among which Al2O3 is preferentially generated and then covered by rapidly growing TiO2 as the thermal exposure duration increases. The nitrides appear later than the oxides and exist between the oxides and the substrate. With increasing exposure temperature and duration, the surface scale becomes more continuous, TiO2 particles grow larger, and the oxide layer thickens or even falls off. The addition of Ta and Nb can improve the oxidation resistance because Ta5+ and Nb5+ replace Ti4+ in the rutile lattice and weaken O diffusion. Compared with the P–HIP Ti–48Al–3Nb–1.5Ta alloy, after thermal exposure, the grain size does not increase significantly, and the γ phase increases slightly (by less than 3%) with the decomposition of the α2 phase. With increasing thermal exposure duration, the γ phase exhibits discontinuous coarsening (DC). Compared with the P–HIP Ti–48Al–3Nb–1.5Ta alloy, the hardness increases by about 2 GPa, the tensile strength increases by more than 50 MPa, and the fracture strain decreases by about 0.1% after thermal exposure. When the depth extends from the edge of the thermally exposed specimens, the hardness decreases overall.

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“…In the research of alloying, the addition of niobium (chemical symbol Nb, atomic number 41) is widely covered. The studies show that the service temperature of the high Nb containing TiAl alloy can be increased by 60–100 °C and the high–temperature yield strength can be doubled, compared with the ordinary TiAl alloy [ 12 ]. Meanwhile, the high–temperature oxidation resistance has reached the level of the nickel-based superalloy for turbine disk [ 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Microstructure Sensitivity on Environmental Embrittlement of a High Nb Containing TiAl Alloy under Different Atmospheres

Zhang

et al. 2022

Materials

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Mechanical properties in different atmospheres, including oxygen, vacuum, air and H2, of high Nb containing TiAl alloys with the compositions of Ti–45Al–8.5Nb–(0.2W, 0.2B, 0.02Y) have been investigated in this work. Three different microstructure types, nearly lamellar, gamma phase increased nearly lamellar and fully lamellar are selected for revealing the microstructure sensitivity of environmental embrittlement. The results show that the three types of microstructures are all affected by the hydrogen–induced environmental embrittlement. Although the fracture mode of the experimental alloy is cleavage fracture in all atmospheres, the proportions of transgranular and intergranular fractures are different, especially comparing the fracture surfaces in oxygen and hydrogen. Performance comparison results show that the nearly lamellar microstructure is the most susceptible to the hydrogen–induced environmental embrittlement, while the gamma phase increased microstructure is the most stable one; the fully lamellar microstructure results in moderate susceptibility to the atmospheres. Combined with the hydrogen absorption kinetic analysis, it indicates that γ phase at the interface of lamellar colony significantly inhibits the hydrogen–induced environmental embrittlement, while the effect of β phase is just the opposite. In addition, the correlation between microstructure and hydrogen–induced environmental embrittlement is revealed and the corresponding mechanism is also discussed in this work.

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Resistance to High-Temperature Oxidation of Ti-Al-Nb Alloys

Cited by 6 publications

References 38 publications

Effects of Structural Radiation Disorder in the Near-Surface Layer of Alloys Based on NbTiVZr Compounds Depending on the Variation of Alloy Components

Effects of Structural Radiation Disorder in the Near-Surface Layer of Alloys Based on NbTiVZr Compounds Depending on the Variation of Alloy Components

Effects of Thermal Exposure on the Microstructure and Mechanical Properties of a Ti–48Al–3Nb–1.5Ta Alloy via Powder Hot Isostatic Pressing

Microstructure Sensitivity on Environmental Embrittlement of a High Nb Containing TiAl Alloy under Different Atmospheres

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