Oxidation behaviour and related microstructural changes of two β0–phase containing TiAl alloys between 600 °C and 900 °C

Mengis, Lukas; Ulrich, Anke Silvia; Watermeyer, Philipp; Liebscher, Christian; Galetz, Mathias C.

doi:10.1016/j.corsci.2020.109085

Cited by 29 publications

(5 citation statements)

References 32 publications

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“…Globular  o -grains at the surface, however, negatively influence the oxidation behavior. Therefore, the microstructure and, more specifically, the phase distribution affect the oxidation resistance and thus have to be taken into account [31,32].…”

Section: Discussionmentioning

confidence: 99%

Effects of tungsten alloying and fluorination on the oxidation behavior of intermetallic titanium aluminides for aerospace applications

et al. 2021

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Section: Discussionmentioning

confidence: 99%

Effects of tungsten alloying and fluorination on the oxidation behavior of intermetallic titanium aluminides for aerospace applications

et al. 2021

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“…Due to the inward diffusion of O during thermal exposure in the range of the service temperature, this particular phase partially transformed into α 2 needles or a mixture of α 2 and γ phase in a TNM alloy. [ 268–270 ] Similarly, the β o phase transformed into α 2 and a Cr 2 Ti‐type Laves phase in the GE‐4822 alloy via a eutectoid decomposition in a temperature interval comparable to the one the TNM alloy was subjected to. [ 269 ] Ultimately, the increase of the material's overall O solubility due to the high solubility within the formed α 2 phase was identified as a contributing factor to the driving force of these transformations.…”

Section: Effect Of Additional Alloying Elements On the Phase Transfor...mentioning

confidence: 99%

“…[ 268–270 ] Similarly, the β o phase transformed into α 2 and a Cr 2 Ti‐type Laves phase in the GE‐4822 alloy via a eutectoid decomposition in a temperature interval comparable to the one the TNM alloy was subjected to. [ 269 ] Ultimately, the increase of the material's overall O solubility due to the high solubility within the formed α 2 phase was identified as a contributing factor to the driving force of these transformations. [ 271 ]…”

Section: Effect Of Additional Alloying Elements On the Phase Transfor...mentioning

confidence: 99%

Alloying Elements in Intermetallic γ‐TiAl Based Alloys – A Review on Their Influence on Phase Equilibria and Phase Transformations

et al. 2023

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Intermetallic γ–TiAl based alloys are innovative structural materials dedicated to applications in the automotive and aeronautic industry. Especially their low density, high specific yield strength and excellent resistance against creep and oxidation make them a suitable choice for structural high‐temperature components in combustion engines. However, further improvement of their properties and processability is required to conquer new application areas and facilitate cost‐effective production. While the incorporation of additional alloying elements is a promising possibility, their effects on the phase transformations and phase equilibria need to be considered rigorously. In this context, this review provides a detailed survey of the research work on the influence of technically important alloying elements on the Ti–Al phase diagram. First, an introduction to the fundamentals of the phase transformations in γ‐TiAl based alloys and the consequences of changed cooling conditions, relevant for example to the latest developments within the field of processing, is given. Afterwards, the alloying elements, categorized with respect to their stabilization effect, are discussed and their particularities highlighted. Topics covered include established ternary phase diagrams and isoplethal sections, the stabilization of additional phases as well as the influence of alloying elements on the microstructure of modern engineering intermetallic γ‐TiAl based alloys.This article is protected by copyright. All rights reserved.

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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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Oxidation behaviour and related microstructural changes of two β0–phase containing TiAl alloys between 600 °C and 900 °C

Cited by 29 publications

References 32 publications

Effects of tungsten alloying and fluorination on the oxidation behavior of intermetallic titanium aluminides for aerospace applications

Effects of tungsten alloying and fluorination on the oxidation behavior of intermetallic titanium aluminides for aerospace applications

Alloying Elements in Intermetallic γ‐TiAl Based Alloys – A Review on Their Influence on Phase Equilibria and Phase Transformations

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

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