Microscale mechanical properties of ultra-high-strength polysynthetic TiAl-Ti 3 Al single crystals

Wang, D.P.; Qi, Zhixiang; Zhang, Hongti; Chen, G.; Lü, Yang; Sun, Baoan; Liu, C.T.

doi:10.1016/j.msea.2018.06.076

Cited by 27 publications

(2 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The nanohardness of the α 2 phase was higher and reached values ranging from 7.4 to 9.3 GPa. Slightly different values were also obtained by Wang et al [67], but nevertheless, the hardness ratio of γ to α 2 phases was approximately the same. Thus, in a first approximation, one can conclude that the presence of the γ phase commonly reduces the hardness of the alloy.…”

Section: Discussionmentioning

confidence: 56%

Structure and Properties of Ti-Al-Ta and Ti-Al-Cr Cladding Layers Fabricated on Titanium

Lazurenko

Golkovsky

Stark

et al. 2021

Metals

View full text Add to dashboard Cite

Being one of the most high-demand structural materials, titanium has several disadvantages, including low resistance to high-temperature oxidation and wear. The properties of titanium and its alloys can be improved by applying protective intermetallic coatings. In this study, 2 mm thick Ti-Al-Ta and Ti-Al-Cr layers were obtained on titanium workpieces by a non-vacuum electron-beam cladding. The microstructure and phase compositions of the samples were different for various alloying elements. The Cr-containing layer consisted of α2, γ, and B2 phases, while the Ta-containing layer additionally consisted of ω′ phase (P3m1). At the same atomic concentrations of aluminum and an alloying element in both layers, the volume fraction of the B2/ω phase in the Ti-41Al-7Ta alloy was significantly lower than in the Ti-41Al-7Cr alloy, and the amount of γ phase was higher. The Ti-41Al-7Cr layer had the highest wear resistance (2.1 times higher than that of titanium). The maximum oxidation resistance (8 times higher compared to titanium) was observed for the Ti-41Al-7Ta layer.

show abstract

Section: Discussionmentioning

confidence: 56%

Structure and Properties of Ti-Al-Ta and Ti-Al-Cr Cladding Layers Fabricated on Titanium

Lazurenko

Golkovsky

Stark

et al. 2021

Metals

View full text Add to dashboard Cite

show abstract

“…However, there are limited reports of lattice strains in the constituent phases of a TiAl alloy, which should be a guide for TiAl microstructure design and can further the understanding of the LCF mechanism. [ 15,18–20 ] With respect to crack propagation, lattice strain in the γ phase and the α 2 phase plays a key role. It shows that large differences of the value and direction of lattice strains in the γ and α 2 phases make cracks propagate along γ/α 2 lamellar interfaces, thus resulting in interlamellar fracture.…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability and Lattice Strain Evolution of High‐Nb‐Containing TiAl Alloy under Low‐Cycle‐Fatigue Loading

et al. 2021

View full text Add to dashboard Cite

The micromechanical behavior and the effect of temperature on the micromechanical mechanism of high‐Nb‐containing TiAl alloy during low‐cycle fatigue still remain uncertain. Herein, in situ and ex situ synchrotron‐based high‐energy X‐ray (HEXRD) experiment results reveal that the γ and ωo phases suffer compressive lattice strains but the lattice strain in the α2 phase evolves from tensile to compressive during low‐cycle fatigue at 900 °C. In addition, the three phases suffer compressive lattice strains during cooling to room temperature, which could result in larger compressive lattice strains in γ and ωo phases and the change of the lattice strain state in the α2 phase. The peak‐broadening results show γ recrystallization is dominant in the interrupted low‐cycle‐fatigue samples, whereas inhomogeneous deformation occurs in the failed low‐cycle‐fatigue samples. The performed synchrotron diffraction experiments offer a deeper insight into the phase transformations and micromechanism of TiAl alloy during low‐cycle fatigue.

show abstract

Improved Fracture Toughness of Polycrystalline γ‐TiAl‐Based Intermetallic Alloys with a Favorable Deformation Mechanism of Twinning

et al. 2022

View full text Add to dashboard Cite

High-density deformation nanotwins markedly strengthen TiAl-based alloys; however, the improvement in strength generally leads to a reduction in fracture toughness for most structural materials. It is, therefore, necessary to investigate the benefits of high-density deformation nanotwins for the improvement in fracture toughness of TiAl-based alloys. Herein, the fracture toughness of two Ti-45.5Al-4Cr-2.5Nb alloys with a favorable deformation mechanism of twinning (prepared by annealing the continuous casting (C. C.) alloy at 1250 C and 1270 C for different durations, respectively) is investigated and compared with that of the unannealed continuous casting (C. C.) alloy, in terms of room-temperature (RT) tensile properties and microstructures. It is found that the two heattreated Ti-45.5Al-4Cr-2.5Nb alloys exhibits a higher fracture toughness than the C. C. alloy. Shear ligaments and slip bands are the main toughening mechanisms for the two heat-treated alloys; their generation is closely related to the enhancement in the plastic deformability of lamellar structures. In addition, the increase in (B2 þ γ)-coupled structures is found to impose a negative effect on the toughening of the investigated alloys. High-density deformation nanotwins favor the improvement in fracture toughness of TiAl-based alloys by improving their fracture strength and plastic deformability, while decreasing their workhardening exponent.

show abstract

Microscale mechanical properties of ultra-high-strength polysynthetic TiAl-Ti 3 Al single crystals

Cited by 27 publications

References 36 publications

Structure and Properties of Ti-Al-Ta and Ti-Al-Cr Cladding Layers Fabricated on Titanium

Structure and Properties of Ti-Al-Ta and Ti-Al-Cr Cladding Layers Fabricated on Titanium

Thermal Stability and Lattice Strain Evolution of High‐Nb‐Containing TiAl Alloy under Low‐Cycle‐Fatigue Loading

Improved Fracture Toughness of Polycrystalline γ‐TiAl‐Based Intermetallic Alloys with a Favorable Deformation Mechanism of Twinning

Contact Info

Product

Resources

About