Effects of extrusion deformation on microstructure, mechanical properties and hot workability of β containing TiAl alloy

Wang, Xu; Shan, De Bin; Zhang, H.; Li, X.A.; Zhang, Y. Z.; Nutt, Steven

doi:10.1016/j.msea.2013.02.005

Cited by 33 publications

(7 citation statements)

References 32 publications

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“…[1,2] However, the application of g-TiAl alloys is limited due to the intrinsic brittleness and hard processability of ordered structure. [3,4] As far as mechanical properties and processability are concerned, the addition of Nb improves the yield strength, fatigue property, oxidation resistance, and hotworkability. Therefore, the high Nb containing TiAl alloys have attracted much attention.…”

Section: Introductionmentioning

confidence: 99%

Recrystallization Behavior at Diffusion Bonding Interface of High Nb Containing TiAl Alloy

Tang

Kou

et al. 2015

Adv Eng Mater

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A series of diffusion bonding tests are conducted on a high Nb containing TiAl alloy with full lamellar (FL) microstructure and the effect of interfacial recrystallization behavior on the shear strength is discussed. Microstructural observations reveal that bonding above 1 100 C and 30 MPa results in recrystallization at the bonding interface flanked by FL microstructure, thus promoting the interface migration and leading to a sound joint. Based on the present results, the nucleation mechanism of recrystallization at the bonding interface is studied. Shear testing results show that recrystallization at the bonded zone improves the bonding quality of the joints by changing the failure mode. The shear strength of the joints attains 400 MPa when bonding at 1 150 C/30 MPa/45 min and 1 100 C/40 MPa/45 min.

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Section: Introductionmentioning

confidence: 99%

Recrystallization Behavior at Diffusion Bonding Interface of High Nb Containing TiAl Alloy

Tang

Kou

et al. 2015

Adv Eng Mater

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“…It is evident that the grain size is one of the critical parameters for fatigue and tensile strength [ 26 ]. Using increasing deformation ratios, the grain size can be decreased significantly, which is mainly attributed to recrystallization leading to a refined and early texture-free microstructure [ 8 , 27 , 28 ].…”

Section: Resultsmentioning

confidence: 99%

An Advanced TiAl Alloy for High-Performance Racing Applications

Burtscher

Klein

Lindemann³

et al. 2020

Materials

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Requirements and strict regulations for high‑performance racing applications involve the use of new and innovative lightweight structural materials. Therefore, intermetallic γ‑TiAl-based alloys enable new opportunities in the field due to their lower density compared to commonly used Ni‑base superalloys. In this study, a β‑solidifying TiAl alloy was examined toward its use as structural material for inlet and outlet valves. The nominal composition of the investigated TNM alloy is Ti–43.5Al–4Nb–1Mo–0.1B (in at%), which enables an excellent formability at elevated temperatures due to the presence of bcc β‑phase. Different hot‑extrusion tests on an industrial scale were conducted on the cast and hot isostatic pressed material to determine the ideal microstructure for the respective racing application. To simulate these operation conditions, hot tensile tests, as well as rotational bending tests, at room temperature were conducted. With a higher degree of deformation, an increasing strength and fatigue limit was obtained, as well as a significant increment of ductility. The fracture surfaces of the rotational bending test specimens were analyzed using scanning electron microscopy, revealing the relationship between crack initiation and microstructural constituents. The results of this study show that the mechanical performance of extruded TiAl material can be tailored via optimizing the degree of hot-extrusion.

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“…TiAl-based alloys with low density and excellent high-temperature properties are considered promising light high-temperature structural materials for aerospace applications, such as inlet flaps, nozzle sidewalls for turbine engines, and thermal protection systems for scramjets [ 1 , 2 , 3 , 4 , 5 ]. Several studies have focused on improving the mechanical properties of these alloys by breaking down the lamellar colonies and refining the grains via alloying-element additions [ 6 , 7 ], heat treatment [ 8 , 9 ], and thermomechanical processing (e.g., hot-forging [ 10 ], extrusion [ 11 ], rolling [ 12 , 13 , 14 ]). Hot pack-rolling processing, as the most practical hot-working method for TiAl alloy sheet production, will probably be required for the fabrication of various TiAl alloy structural components with complex shapes.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Recrystallization of the Constituent γ Phase and Mechanical Properties of Ti-43Al-9V-0.2Y Alloy Sheet

Wang

Kong

et al. 2017

Materials

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Abstract:A crack-free Ti-43Al-9V-0.2Y alloy sheet was successfully fabricated via hot-pack rolling at 1200 • C. After hot-rolling, the β/γ lamellar microstructure of the as-forged TiAl alloy was completely converted into a homogeneous duplex microstructure with an average γ grain size of 10.5 µm. The dynamic recrystallization (DRX) of the γ phase was systematically investigated. A recrystallization fraction of 62.5% was obtained for the γ phase in the TiAl alloy sheet, when a threshold value of 0.8 • was applied to the distribution of grain orientation spread (GOS) values. The high strain rate and high stress associated with hot-rolling are conducive for discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX), respectively. A certain high-angle boundary (HAGB: θ = 89 • ± 3 • <100>), which is associated with DDRX, occurs in both the recrystallized and deformed γ grains. The twin boundaries play an important role in the DDRX of the γ phase. Additionally, the sub-structures and sub-boundaries originating from low-angle boundaries in the deformed grains also indicate that CDRX occurs. The mechanical properties of the alloy sheet were determined at both room and elevated temperatures. At 750 • C, the alloy sheet exhibited excellent elongation (53%), corresponding to a failure strength of 467 MPa.

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Effects of extrusion deformation on microstructure, mechanical properties and hot workability of β containing TiAl alloy

Cited by 33 publications

References 32 publications

Recrystallization Behavior at Diffusion Bonding Interface of High Nb Containing TiAl Alloy

Recrystallization Behavior at Diffusion Bonding Interface of High Nb Containing TiAl Alloy

An Advanced TiAl Alloy for High-Performance Racing Applications

Dynamic Recrystallization of the Constituent γ Phase and Mechanical Properties of Ti-43Al-9V-0.2Y Alloy Sheet

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