Effects of Microstructure, Alloying and C and Si Additions on Creep of Gamma TiAl Alloys

Kim, Young‐Won; Kim, Sang‐Lan

doi:10.1002/9781118998489.ch24

Cited by 5 publications

(8 citation statements)

References 19 publications

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“…turbochargers). The low density (high specific strength) of γ -TiAl makes it more attractive than Ni-based superalloys for a variety of structural components in critical aerospace applications [18, 19, 94-98]. The investigations resulted in better control of alloy composition, melt casting, powder processing, and microstructure through thermomechanical processing and innovative heat treatments [99-109].…”

Section: Tial-based Alloysmentioning

confidence: 99%

“…γ -TiAl has an L1 0 ordered face-centered tetragonal structure, and it remains ordered up to its melting point (1450°C). Another important phase constituent in the Ti/Al phase diagram (see Figure 22) is α 2 (Ti 3 Al) [97, 108]. The most practical alloy is the two-phased γ -TiAl + α 2 (Ti 3 Al).…”

Section: Tial-based Alloysmentioning

confidence: 99%

“…At temperatures higher than 1125°C, α 2 has a disordered hexagonal close-packed structure; it has an ordered DO 19 structure below the critical temperature. The phase diagram of Ti–Al indicates that the Al content in the γ phase ranges from 45 to 52 at.-% [97, 101, 108]. The phase diagram also shows the presence of other forms of aluminides, such as Ti 3 Al ( α 2 ) and Al 3 Ti.…”

Section: Tial-based Alloysmentioning

confidence: 99%

“…Figure 23 shows crystal structures of both γ -TiAl and α 2 (Ti 3 Al) phases.

Figure 22 Binary phase diagram of Ti/Al system [97].

Figure 23 Crystal structure of γ -TiAl and α 2 (Ti 3 Al) [110].…”

Section: Tial-based Alloysmentioning

confidence: 99%

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Welding of unique and advanced ductile intermetallic alloys for high-temperature applications

David

Deevi

2017

Science and Technology of Welding and Joining

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Intermetallic alloys represent a unique class of materials with atomic arrangements that are different from those of conventional disordered alloys. Among them are alloys based on Ni 3 Al, Fe 3 Al, and TiAl. Intermetallic alloys have unique properties, such as high melting point, low density, high-temperature strength, and high-temperature corrosion and oxidation resistance. Their only disadvantage is the lack of ductility at room temperature and at elevated temperatures. However, they can be ductilised by micro-and macroalloying. Application of intermetallic alloys for structural use at elevated temperature depends on their ability to be welded using conventional welding procedures. This paper focuses on the development of these alloys, their behaviour when subjected to weld thermal cycles, and their weldability. Most intermetallic alloys are susceptible to cracking during or after welding, but some can be modified to have good weldability. The paper discusses welding and weldability of Ni 3 Al-, Fe 3 Al-, and TiAl-based intermetallic alloys. In addition, the weldability of other long-range ordered alloys, of the type (Fe, Ni) 3 V and (Fe, Co) 3 V, are briefly discussed.

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Section: Tial-based Alloysmentioning

confidence: 99%

Section: Tial-based Alloysmentioning

confidence: 99%

Section: Tial-based Alloysmentioning

confidence: 99%

“…Figure 23 shows crystal structures of both γ -TiAl and α 2 (Ti 3 Al) phases.

Figure 22 Binary phase diagram of Ti/Al system [97].

Figure 23 Crystal structure of γ -TiAl and α 2 (Ti 3 Al) [110].…”

Section: Tial-based Alloysmentioning

confidence: 99%

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Welding of unique and advanced ductile intermetallic alloys for high-temperature applications

David

Deevi

2017

Science and Technology of Welding and Joining

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“…γ-TiAl-based alloys are considered highly promising materials for aeroengine and automotive applications because of their attractive properties, including low density, high-temperature strength, good oxidation, and creep resistance at elevated temperatures [1,2,3,4]. Recently, an advanced γ-TiAl-based alloy called beta–gamma TiAl-based alloy has gradually aroused researchers’ interest because it has good hot workability, homogeneous microstructures, weak textures, and minimal segregation [5]. Different from traditional γ-TiAl-based alloys, which contain two basic phases (i.e., γ-TiAl and α 2 -Ti 3 Al) and often small amounts of the β 0 phase, the beta–gamma TiAl-based alloy is a multiphase alloy that consists of three major phases (i.e., γ-TiAl, α 2 -Ti 3 Al and β 0 -Ti) and an additional phase (i.e., ω 0 -Ti 4 Al 3 Nb), which usually co-exists with the β 0 phase [6,7].…”

Section: Introductionmentioning

confidence: 99%

Microstructural Evolution and Refinement Mechanism of a Beta–Gamma TiAl-Based Alloy during Multidirectional Isothermal Forging

Zhu

et al. 2019

Materials

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Multidirectional isothermal forging (MDIF) was used on a Ti-44Al-4Nb-1.5Cr-0.5Mo-0.2B (at. %) alloy to obtain a crack-free pancake. The microstructural evolution, such as dynamic recovery and recrystallization behavior, were investigated using electron backscattered diffraction and transmission electron microscopy methods. The MDIF broke down the initial near-lamellar microstructure and produced a refined and homogeneous duplex microstructure. γ grains were effectively refined from 3.6 μm to 1.6 μm after the second step of isothermal forging. The ultimate tensile strength at ambient temperature and the elongation at 800 °C increased significantly after isothermal forging. β/B2→α2 transition occurred during intermediate annealing, and α2 + γ→β/B2 transition occurred during the second step of isothermal forging. The refinement mechanism of the first-step isothermal forging process involved the conversion of the lamellar structure and discontinuous dynamic recrystallization (DDRX) of γ grains in the original mixture-phase region. The lamellar conversion included continuous dynamic recrystallization and DDRX of the γ laths and bugling of the γ phase. DDRX behavior of γ grains dominated the refinement mechanism of the second step of isothermal forging.

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Preparation of Sr2CeZrO6 Refractory and Its Interaction with TiAl Alloy

Bian,

Cai,

Liu

et al. 2023

Materials

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Vacuum induction melting in a refractory crucible is an economical method to produce TiAl-based alloys, aiming to reduce the preparation cost. In this paper, a Sr2CeZrO6 refractory was synthesized by a solid-state reaction method using SrCO3, CeO2 and ZrO2 as raw materials, and its interaction with TiAl alloy melt was investigated. The results showed that a single-phase Sr2CeZrO6 refractory could be fabricated at 1400 °C for 12 h, and its space group was Pnma with a = 5.9742(3) Å, b = 8.3910(5) Å and c = 5.9069(5) Å. An interaction layer with a 40μm thickness and dense structure could be observed in Sr2CeZrO6 crucible after melting TiAl alloy. Additionally, the interaction mechanism showed that the Sr2CeZrO6 refractory dissolved in the alloy melt, resulting in the generation of Sr3Zr2O7, SrAl2O4 and CeO2−x, which attached to the surface of the crucible.

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Effects of Microstructure, Alloying and C and Si Additions on Creep of Gamma TiAl Alloys

Cited by 5 publications

References 19 publications

Welding of unique and advanced ductile intermetallic alloys for high-temperature applications

Welding of unique and advanced ductile intermetallic alloys for high-temperature applications

Microstructural Evolution and Refinement Mechanism of a Beta–Gamma TiAl-Based Alloy during Multidirectional Isothermal Forging

Preparation of Sr2CeZrO6 Refractory and Its Interaction with TiAl Alloy

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