Alloy modification of γ-base titanium aluminide for improved oxidation resistance, creep strength and fracture toughness

Tsuyama, Seishi; Mitao, Shinji; Minakawa, Kuninori

doi:10.1016/0921-5093(92)90236-t

Cited by 80 publications

(13 citation statements)

References 4 publications

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“…Nevertheless, even if the niobium content is reduced here, niobium will contribute to the increase in lattice parameter as well so that a clear distinction is impossible. (5) The lattice parameter of the niobium enriched region (as identified by the EDS mappings) is increased compared to pure -titanium and the Ti 2Nb matrix, verifying the results of the EDS mappings and point analyses.…”

Section: Micro-focussed Hard X-ray Experimentssupporting

confidence: 63%

“…It has to be taken into account that, on the one hand, increasing niobium contents are favourable with respect to oxidation resistance but, on the other hand, alloy production gets more difficult with increasing niobium contents as the probability of high-density inclusion formation (HDIs) is increased. From earlier investigations, the addition of 0.4% silicon to a > 0.5% niobium containing alloy is advisable to improve the oxidation behaviour of conventional titanium alloys [5] We have discovered severe differences between the niobium and vanadium distribution in the metal matrix of binary titanium alloys during oxidation (indicating that not only the 5 + -charge of the ions is important). This can most likely be explained by the differences of the solvability of vanadium and niobium intitanium, their different diffusion rates in -titanium and their interaction with the oxygen penetrating the metal matrix at the metal-oxide-interface.…”

Section: Discussionmentioning

confidence: 93%

“…Considerable efforts have been made since the late 1980ies to improve the oxidation resistance of titanium alloys at elevated temperature of both, conventional titanium alloys and titanium alumindes [5]. The two most effective elements are silicon and niobium [6].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

How Does Niobium Improve The Oxidation Resistance of Commercially Pure Titanium

Ackland¹,

Siemers

Tegner³

et al. 2016

Proceedings of the 13th World Conference on Titanium

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The application of titanium alloys is limited to 550°C due to their poor oxidation resistance. It is known that the addition of niobium decelerates the oxidation of titanium alloys whereas elements like vanadium do not improve titanium's oxidation resistance. The underlying mechanisms are not yet well understood. In the present study, different binary titanium-niobium and titanium-vanadium alloys as well as commercially pure titanium were investigated. Oxidation experiments were carried out at 800°C up to 288 hours followed by metallographic analyses to study the oxide layer morphology as well as the microstructure at the interface. Energydispersive X-ray spectroscopy mappings were used to identify possible changes in the distribution of the alloying elements. In addition, micro-focused hard X-ray experiments were performed to layer-wise analyse the phase composition in selected samples. As expected, the niobium containing alloys show a better oxidation performance compared to commercially pure titanium and the titanium-vanadium alloys. The oxide layer consisted of TiO 2 and Ti 2 O 3 . Depending of the niobium content, a niobiumrich layer developed below the metal-oxide-interface minimising oxygen diffusion into the titanium matrix. Based on these results, the minimal niobium content needed for improved oxidation resistance was identified so that alloys of technical relevance can now be developed.

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Section: Micro-focussed Hard X-ray Experimentssupporting

confidence: 63%

Section: Discussionmentioning

confidence: 93%

See 1 more Smart Citation

How Does Niobium Improve The Oxidation Resistance of Commercially Pure Titanium

Ackland¹,

Siemers

Tegner³

et al. 2016

Proceedings of the 13th World Conference on Titanium

View full text Add to dashboard Cite

show abstract

“…Considerable efforts have been made since the late 1980s to improve the oxidation resistance of titanium alloys at elevated temperature of both, conventional titanium alloys and titanium alumindes [5]. The two most effective elements are silicon and niobium [6].…”

Section: Introductionmentioning

confidence: 99%

A New Class of Oxidation‐Resistant, Microstructural‐Stabilized and Cold‐Workable Titanium Alloys for Exhaust Applications

Kiese¹,

Siemers

Schmidt³

2016

Proceedings of the 13th World Conference on Titanium

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The application of conventional titanium alloys is limited to 550°C due to their poor oxidation resistance. In addition, severe grain growth is observed in single-phase titanium alloys in longterm runs at elevated temperature leading to a degradation of their mechanical properties. In exhaust applications in automotive or aerospace engineering, products are often manufactured by colddeformation like deep-drawing or rolling which is normally difficult in oxidation-resistant titanium alloys due to the presence of titanium-silicides.Therefore, in the current study, titanium alloys based on CP Titanium Grade 1S (soft grade) were developed showing (1) improved oxidation resistance due to a concerted addition of silicon, iron and niobium, (2) microstructure stability by the precipitation of hafnium-silicides mainly on the grain boundaries and (3) good cold-deformation properties. The industrial production route was developed so that the new class of Ti-Si-FeNb-Hf-alloys is now ready for application in exhaust systems of planes or cars at minimum 800°C.

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“…Some works have demonstrated that the addition of Si can modify the microstructures and improve the high temperature properties of £-TiAl alloys. 12,13) However, for the ¢ stabilized TiAl alloys, the effects of Si on the microstructures and the high temperature properties are still unclear. In the present study, the effects of Si addition on the microstructures, the high temperature compressive properties and high temperature creep properties of the ¢-stabilized Ti-45Al-3Fe-2Mo alloy have been studied, and the deformation mechanisms during hot compression and creep are also discussed.…”

Section: Introductionsmentioning

confidence: 99%

Effects of Si on Microstructures and High Temperature Properties of Beta Stabilized TiAl Alloy

Zhou

Zeng²,

Liu

et al. 2016

Mater. Trans.

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The effects of Si addition on microstructures, high temperature compressive properties and creep properties of the ¢-stabilized Ti-45Al-3Fe-2Mo alloy have been studied in this work. The results show that the Si addition decreases the volume fraction of ¢ phase and precipitates particulate Ti 5 Si 3 phase. At the same time, the Si addition improves the high temperature strength of the Ti-45Al-3Fe-2Mo alloy for about 200 MPa at 800°C and decreases the creep strain for about 35% at 800°C under an applied stress of 150 MPa. The decrease in volume fraction of ¢ phase and precipitation of Ti 5 Si 3 particles are believed to be the dominant mechanisms for the improvement of the high temperature properties of the Si-doped TiAl alloy.

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Alloy modification of γ-base titanium aluminide for improved oxidation resistance, creep strength and fracture toughness

Cited by 80 publications

References 4 publications

How Does Niobium Improve The Oxidation Resistance of Commercially Pure Titanium

How Does Niobium Improve The Oxidation Resistance of Commercially Pure Titanium

A New Class of Oxidation‐Resistant, Microstructural‐Stabilized and Cold‐Workable Titanium Alloys for Exhaust Applications

Effects of Si on Microstructures and High Temperature Properties of Beta Stabilized TiAl Alloy

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