Characterization of phase transformation during hot compressive deformation in a β-stabilized Ti–45Al–7Nb–0.4W–0.15B alloy

Liu, Bin; Liu, Yong; Huang, Lan; Li, Huizhong; He, Yuehui

doi:10.1016/j.matchar.2015.05.008

Cited by 10 publications

(2 citation statements)

References 14 publications

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“…During hot deformation, work hardening, dynamic recovery (DRV), dynamic recrystallization (DRX), and phase transformations often occur. Some works are available on the hot deformation behavior and microstructural evolution of β phase containing TiAl, and the compositions therein are Ti-43.5Al-4Nb-1Mo-0.1B [5], Ti-43Al-2Cr-2Mn-0.2Y [6], Ti-43Al-4Nb-1.4W-0.6B-0.2Y [7], and Ti-45Al-7Nb-0.4W-0.15B [8,9]. The lamellar grain sizes of these alloys were all fine because of β-phase solidification and the addition of Band/or Y elements.…”

Section: Introductionmentioning

confidence: 99%

Hot Deformation Behavior and Microstructural Evolution Characteristics of Ti-44Al-5V-1Cr Alloy Containing (γ + α2 + B2) Phases

Liu

Rong

Gao

et al. 2016

Metals

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Abstract:The hot deformation behavior and microstructural evolution of Ti-44Al-5V-1Cr alloy were investigated by hot compression tests at temperatures of 1000-1250 • C and strain rates of 0.001-1 s −1 . It was indicated that the dependence of peak stress on deformation temperature and strain rate could be accurately described by a hyperbolic sine type equation. The activation energy, Q, was estimated to be 632 kJ/mol. The hot processing map was developed at different strains on the basis of dynamic materials modeling and the Murty criteria. As a result, the instability zones occurred in the regions of low temperature (<1050 • C) and a high strain rate (>0.1 s −1 ). The flow soft mechanism of the instability regions is stress relaxation caused by localization deformation at lamellar boundaries. Dynamic recrystallization is the mainly refining and spheroidizing mechanism of lamellar microstructures. The optimum hot working condition of as-cast TiAl alloy occurs in the temperature range of 1175-1225 • C and the strain rate range 0.05-0.1 s −1 . The large-size TiAl alloy rectangular bars with crack-free appearance were successfully prepared by hot extrusion. After annealing, the fine and uniform microstructure with excellent deformation ability was obtained.

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Section: Introductionmentioning

confidence: 99%

Hot Deformation Behavior and Microstructural Evolution Characteristics of Ti-44Al-5V-1Cr Alloy Containing (γ + α2 + B2) Phases

Liu

Rong

Gao

et al. 2016

Metals

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“…In recent years, different thermo-mechanical treatments and many different alloying additions have been explored to increase room temperature ductility, strength, high-temperature mechanical properties and also to improve high-temperature oxidation resistance of TiAl-based alloys [3][4][5][6][7][8][9][10]. Among various alloying elements, special attention was given to the effect of slow diffusing additions of Nb and Ta.…”

Section: Introductionmentioning

confidence: 99%

Cyclic oxidation behaviour of intermetallic Ti-46Al-8Ta alloy in air

Pelachová¹,

Lapin²

2016

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The cyclic oxidation behaviour of intermetallic Ti-46Al-8Ta (at.%) alloy was studied in the air. Long-term oxidation experiments were carried out on the samples with convoluted type of γ(TiAl) + α2(Ti3Al) microstructure at temperatures ranging from 700 to 800• C for oxidation time up to 3100 h. The oxidation kinetics was determined from the weight gain measurements as a function of oxidation time and temperature. The parabolic rate constants and activation energy for oxidation were calculated and discussed. The experimental results showed that the spallation had no significant effect on oxidation kinetic curves at 700 and 760• C up to 3100 h but affected the measured kinetics at 800• C for oxidation time longer than 500 h. The EDS and X-ray diffraction observations showed that the scales consisted of TiO2, α-Al2O3, Ti2AlN, TaAlTi and TiN phases.K e y w o r d s : titanium aluminides, TiAl, cyclic oxidation, microstructure

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The Effect of Pressure Stress on the Evolution of B2(ω) Phase in High Nb Containing TiAl Alloy

et al. 2017

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The thermal stability of the B2(v) phase in high Nb containing TiAl alloy has attracted intense attention in recent years. This study focuses on the phase transformation between B2 and v phases under the influence of thermal pressure stress in the Ti-45Al-8.5Nb-(W, B, Y) alloy. A large number of v phases with the volume fraction of 42.3% exist within the B2 region in as-cast alloys. The as-cast samples were subjected to thermo-compressive loading at 850 and 900 C under the stresses of 300 and 500 MPa. Results show that the transformation of B2 ! v occurs at 850 C, which can be promoted under a pressure stress. Further, the v particles dissolved into the B2 matrix at 900 C, and this transformation is suppressed by the role of thermal pressure. The mechanisms of the phase transformations mentioned above were discussed.

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Characterization of phase transformation during hot compressive deformation in a β-stabilized Ti–45Al–7Nb–0.4W–0.15B alloy

Cited by 10 publications

References 14 publications

Hot Deformation Behavior and Microstructural Evolution Characteristics of Ti-44Al-5V-1Cr Alloy Containing (γ + α2 + B2) Phases

Hot Deformation Behavior and Microstructural Evolution Characteristics of Ti-44Al-5V-1Cr Alloy Containing (γ + α2 + B2) Phases

Cyclic oxidation behaviour of intermetallic Ti-46Al-8Ta alloy in air

The Effect of Pressure Stress on the Evolution of B2(ω) Phase in High Nb Containing TiAl Alloy

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