Characterization of the high temperature deformation behavior of two intermetallic TiAl–Mo alloys

Godor, Flora; Lindemann, Janny; Clemens, Helmut; Mayer, Svea

doi:10.1016/j.msea.2015.09.077

Cited by 40 publications

(15 citation statements)

References 33 publications

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“…Besides, according to Equation (1), the used value of Q in it is critical to the calculation accuracy of Z. As above described, the compression deformation under different parameters of present fine grained γ-TiAl alloy is related to a transition of deformation mechanism between dislocation creep and GBS, which leading to the inapplicability of the average value of Q under different deformation conditions other literatures commonly used [13][14][15][16][17] in the present work. In those literatures, the value of Q does not change with deformation parameters.…”

Section: The Effect Of Compression Parameters On Microstructure Evolumentioning

confidence: 99%

“…As we know, in the practical isothermal forging process, the deformation of the billet is mainly conducted under compressive stress state, and the deformation at different stages of the process and in different parts of the billet could be controlled by different mechanisms (i.e., dislocation creep versus grain boundary sliding (GBS)) corresponding to different deformation conditions (i.e., non-superplastic condition versus superplastic condition). However, the pioneering research works regarding isothermal compression deformation of γ-TiAl alloys [13][14][15][16][17] and superplasticity of γ-TiAl alloys via tension deformation [18][19][20][21][22] rarely involve the above issues. Therefore, in previous works [23,24] a deformation mechanism transition from dislocation creep to GBS with increasing deformation temperature and decreasing strain rate was revealed via the investigation of the isothermal compression of a fine-grained high Nb containing TiAl alloy with a (α 2 + γ) microstructure.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure Evolution of a High Nb Containing TiAl Alloy with (α2 + γ) Microstructure during Elevated Temperature Deformation

Chu

Zhu

et al. 2018

Metals

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In order to verify the correctness of the transition of deformation mechanism with the change in deformation parameters and to reveal the types and mechanism of dynamic recrystallization of γ grains during compression deformation, microstructure characterization of Ti-43.5Al-8Nb-0.2W-0.2B (at. %) alloy after isothermal compression deformation were performed. When the alloy was deformed at 1000 • C/10 −2 s −1 , the initial γ grains are elongated and significantly refined and the fraction of low angle grain boundaries (LAGB) of γ grains is obviously increased and the texture intensity remains unchanged, which indicates that the compression deformation in dislocation creep region is dominated by intragranular deformation and dynamic recrystallization (DRX) of γ grains. Besides, the lattice rotation at grain boundary serrations may be responsible for the nucleation of new recrystallized γ grains, and the following growth process may be achieved by the migration of γ grain boundaries. However, when the alloy deformed at 1050 • C/10 −4 s −1 and 1000 • C/10 −4 s −1 , the γ grains maintain equiaxed shapes and distribute more uniformly and the fraction of LAGB of γ grains is slightly raised and the texture sharpness decreases, which indicates that the compression deformation in grain boundary sliding (GBS) region is mainly controlled by GBS of γ grains and DRX occurs simultaneously within some coarse γ grains.

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Section: The Effect Of Compression Parameters On Microstructure Evolumentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure Evolution of a High Nb Containing TiAl Alloy with (α2 + γ) Microstructure during Elevated Temperature Deformation

Chu

Zhu

et al. 2018

Metals

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“…Werner et al [17] and Godor et al [18] applied two phenomenological constitutive models for the description of the hot deformation behavior of different TiAl-alloys, the Sellars-McTegart (ST) model and the Hensel-Spittel (HS) model. Werner et al [17] investigated the flow behavior of a β-solidifying TNM (TiAl with Nb and Mo as the main alloying elements) alloy with the nominal composition Ti-43.5Al-4Nb-1Mo-0.1B.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Werner et al [17] investigated the flow behavior of a β-solidifying TNM (TiAl with Nb and Mo as the main alloying elements) alloy with the nominal composition Ti-43.5Al-4Nb-1Mo-0.1B. Godor et al [18] investigated two γ-TiAl alloys with the nominal compositions Ti-41Al-3Mo-0.5Si-0.1B and Ti-45Al-3Mo-0.5Si-0.1B. Both authors found that the ST model gave good predictions for flow stress, however the model is only valid in the experimental strain range from which the constitutive expression has been derived.…”

Section: Literature Reviewmentioning

confidence: 99%

Batch Processing in Preassembled Die Sets—A New Process Design for Isothermal Forging of Titanium Aluminides

Bambach

Sizova

Sviridov

et al. 2018

JMMP

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Titanium aluminide (TiAl) turbine blades produced by isothermal forging have recently been implemented in the low-pressure part of commercial aircraft jet engines. However, the slow speed of isothermal forging, costly molybdenum-based dies and the required protective forging atmosphere makes the process rather expensive. Currently, industrial forging is done by closed-die isothermal forging processes with stationary dies. Idle time occurs when single parts are inserted and extracted from the dies. As an interesting alternative for forging small parts, a new set-up is devised and explored in this work, i.e., batch processing. Using a die set which allow for off-line preassembly and preheating, multiple parts can be forged in one stroke. The design of the batch process was based on a new material model, which was implemented into a finite element system to identify the forging parameters. The setup of the press transport system for batch processing, as well as the results of the simulations and forging experiments are presented. A cost comparison between the new process and conventional forging with stationary dies concludes that for smaller parts such as compressor blades, batch processing offers advantages regarding productivity and cost.

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“…A large number of 2 of 16 studies have proven that the addition of the alloying element Mo to TiAl-based alloys is an effective method to reduce the flow stress of TiAl-based alloys [8]. Godor et al [9] studied the high-temperature deformation behavior of a high Mo-TiAl alloy, and found that the true stress-strain curve of the Ti-45Al-3Mo-0.5Si-0.1B alloy presented typical dynamic recrystallization softening characteristics. Based on the actual compression results, it was found that TiAl-based alloys had a relatively low flow stress and excellent thermal processing performance under the conditions of higher than 1100 • C and lower than 0.01 s −1 .…”

Section: Introductionmentioning

confidence: 99%

Effect of 0.8 at.% H on the Mechanical Properties and Microstructure Evolution of a Ti–45Al–9Nb Alloy Under Uniaxial Tension at High Temperature

Ding

Wang

et al. 2020

Coatings

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To investigate the effect of hydrogen on the high-temperature deformation behaviors of TiAl-based alloys, the high-temperature tensile experiment was carried out on a Ti–45Al–9Nb (at.%) alloy with the H content of 0 and 0.8 at.%, respectively. Then, the effect of hydrogen on the high-temperature mechanical properties of the as-cast alloy was studied, the constitutive relations among stress, temperature, and strain rate were established, and the microstructure was analyzed. The results indicated that, compared with the unhydrogenated alloy, the flow stress of the hydrogenated alloy was significantly reduced, and the peak stress of the hydrogenated alloy decreased by (16.28 ± 0.17)% deformed at 1150 °C/0.0004 s−1. Due to the presence of hydride (TiAl)Hx in the alloy, the elongation showed a decline trend with increasing strain rate at the same deformation temperature. Compared with the unhydrogenated alloy, the elongation of the hydrogenated alloy reduced by (26.05 ± 0.45)% (0.0004 s−1), (23.49 ± 0.38)% (0.001 s−1), and (14.23 ± 0.19)% (0.0025 s−1), respectively, indicating that 0.8 at.% H softened the Ti–45Al–9Nb alloy and reduced the high-temperature plastic deformability. Under the same deformation condition, the deformation extent of the hydrogenated alloy was less than that of the unhydrogenated alloy. There were more residual lamellae in the hydrogenated alloy, and the extent of dynamic recrystallization was lower than that of the unhydrogenated alloy.

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Characterization of the high temperature deformation behavior of two intermetallic TiAl–Mo alloys

Cited by 40 publications

References 33 publications

Microstructure Evolution of a High Nb Containing TiAl Alloy with (α2 + γ) Microstructure during Elevated Temperature Deformation

Microstructure Evolution of a High Nb Containing TiAl Alloy with (α2 + γ) Microstructure during Elevated Temperature Deformation

Batch Processing in Preassembled Die Sets—A New Process Design for Isothermal Forging of Titanium Aluminides

Effect of 0.8 at.% H on the Mechanical Properties and Microstructure Evolution of a Ti–45Al–9Nb Alloy Under Uniaxial Tension at High Temperature

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