Journal ArticleDOI
Positive influence of hydrogen on the hot workability and dynamic recrystallization of a γ-TiAl based alloy
TLDR
In this paper, high temperature deformation behaviors of the unhydrogenated and hydrogenated Ti-46Al-2V-1Cr-0.3Ni alloys were investigated in the temperature range 1050-1200 ǫ c and strain rate range 0.001-1 s−1.Abstract:
High temperature deformation behaviors of the unhydrogenated and hydrogenated Ti-46Al-2V-1Cr-0.3Ni (at%) alloys were investigated in the temperature range 1050–1200 °C and strain rate range 0.001–1 s−1. The flow stress of the hydrogenated alloy was lower than that of the unhydrogenated alloy, which was mainly attributed to hydrogen-promoted lamellar decomposition, twinning and dynamic recrystallization. Processing maps of the unhydrogenated and hydrogenated alloys were constructed. The stability domain of the hydrogenated alloy was enlarged in comparison with that of the unhydrogenated alloy, meaning hydrogen enhanced the hot workability of the Ti-46Al-2V-1Cr-0.3Ni alloy. Hydrogen activated slip systems so that lamellar bending more easily occurred in the hydrogenated alloy, which made inter-lamellar fracture convert into trans-lamellar fracture. Therefore, crack propagation was restrained in the hydrogenated alloy during hot deformation. The critical strain of the hydrogenated alloy was less than those of the unhydrogenated alloy, meaning the dynamic recrystallization occurred earlier in the hydrogenated alloy. γ-phase discontinuous dynamic recrystallization was promoted due to hydrogen addition, leading to a consumption of plentiful dislocations, which restrained continuous dynamic recrystallization to some extent. Hydrogen-promoted discontinuous dynamic recrystallization was mainly attributed to hydrogen-promoted lamellar decomposition, twinning, and hydrogen-decreased stacking fault energy.read more
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Journal ArticleDOI
Microstructure evolution and dynamic softening mechanisms during high-temperature deformation of a precipitate hardening Ni-based superalloy
TL;DR: In this paper, the microstructure evolution of precipitate hardening Ni-based superalloy in the temperature range 1060-1180°C and strain rate range 0.001-10s−1.
Journal ArticleDOI
Dynamic softening behavior and microstructural characterization of TiAl-based alloy during hot deformation
TL;DR: In this paper, the worksoftening transient behavior of a powder metallurgy Ti-47Al-2Nb-2Cr alloy during hot deformation, along with microstructure characterization under a temperature of 950-1150 ǫ c and a broad range of strain rates encompassing 0.001 − 0.1 s− 1, has been investigated.
Journal ArticleDOI
Dynamic recrystallization mechanism of γ and α phases during the isothermal compression of γ-TiAl alloy with duplex structure
R.R. Xu,H. Li,Mingxing Li +2 more
TL;DR: In this paper, the dynamic recrystallization (DRX) mechanism of Ti-4289Al-459Nb-201Cr-025Cu-01Fe-059Si-007W-0004Se with duplex structure was investigated via electron backscatter diffraction (EBSD) when isothermal compression were conducted at the deformation temperatures of 1100-1250°C, strain rates of 0001-001 s−1 and height reductions of 20%-50%.
Journal ArticleDOI
Flow softening mechanism in isothermal compression of β-solidifying γ-TiAl alloy
R.R. Xu,H. Li,Mengzhi Li +2 more
TL;DR: In this paper, the authors investigated the flow softening mechanism in the isothermal compression of Ti-42.9Al-4.6Nb-2Cr with duplex structure.
Journal ArticleDOI
Deformation behavior and microstructural evolution of hydrogenated Ti44Al6Nb alloy during thermo-compression at 1373–1523 K
TL;DR: In this paper, the effect of hydrogen on the hot deformation behaviors of Ti44Al6Nb alloy is investigated at temperature range from 1373k to 1523k and the strain rate range from 0.001 s−−1 to 1 s−1 on Gleeble-1500D thermo-simulation machine.
References
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Journal ArticleDOI
Hydrogen-enhanced localized plasticity—a mechanism for hydrogen-related fracture
TL;DR: In this article, a theory of hydrogen shielding of the interaction of dislocations with elastic stress centres is outlined, which can account for the observed hydrogen-enhanced dislocation mobility.
Journal ArticleDOI
Modeling of dynamic material behavior in hot deformation: Forging of Ti-6242
Y. V. R. K. Prasad,Y. V. R. K. Prasad,H. L. Gegel,S. M. Doraivelu,J. C. Malas,J. T. Morgan,K. A. Lark,D. R. Barker +7 more
TL;DR: In this article, a new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented, which considers the workpiece as a dissipator of power in the total processing system and evaluates the dissipated power co-contentJ = ∫o σ e ⋅dσ from the constitutive equation relating the strain rate (e) to the flow stress (σ).
Journal ArticleDOI
Ordered intermetallic alloys, part III: Gamma titanium aluminides
TL;DR: In this paper, an improved understanding of both fundamental and practical aspects of these aluminides, such as phase relations, microstructure evolution and control, processing, micro-structure-property relationships, and deformation and fracture processes, is presented.
Journal ArticleDOI
Processing and applications of intermetallic γ-TiAl-based alloys
Helmut Clemens,Heinrich Kestler +1 more
TL;DR: In this paper, the authors proposed a high-temperature materials for the next generation of aircraft engines, space vehicles, and automotive engines, and showed that intermetallic γ-TiAl-based alloys show a great potential to fulfill these demands.