Creep resistance and high-temperature metallurgical stability of titanium alloys containing gallium

Shamblen, C. E.; Redden, T.K.

doi:10.1007/bf02642464

Cited by 22 publications

(11 citation statements)

References 6 publications

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“…Conventional near-alpha Ti alloys are strengthened by fine alpha2 phase with DO 19 structure and intermetallic silicides [7][8]. Up to now, numerous works were focused on the influence of alpha stabilizing alloying elements such as Ga, Sn, Hf and Zr on the high temperature mechanical properties of the near-alphaa titanium alloys [9][10]12]. These studies demonstrated that the solid solution strengthening and the formation of a 2 phase are effective in improving high temperature strength, but degrade the ductility of the material [10][11] probably due to the lower symmetry of its DO 19 crystal structure.…”

Section: Introductionmentioning

confidence: 99%

Role of refractory elements in near-alpha titanium alloys on high temperature mechanical properties

et al. 2020

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The effect of Tungsten (W), Tantalum (Ta) and simultaneous addition of Germanium (Ge) and Silicon (Si) on the microstructure evolution, tensile and creep properties of the near-alpha alloy Ti-5.7Al-3.9Sn-3.7Zr-0.7Nb-0.5Mo-0.35Si-0.05C have been investigated at high temperatures up to 650°C. Microstructural characterizations following solution treatment at 1050°C for 2 hours with oil quenching and aging treatment at 700°C for 2 hours followed by air cooling, highlighted that the additions of refractory elements such as W and Ta led to a decrease of both the volume fraction of the primary alpha phase (ap) and its average size. Tensile tests performed up to 650°C revealed a significant improvement in tensile strength with additions of W and Ta, even though a decrease of ductility has been also detected. Creep tests carried out at 600°C under a constant stress of 200 MPa pointed out that, refractory elements, Ge and Si have a beneficial effect on both primary and steady-state creep strain rates.

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Section: Introductionmentioning

confidence: 99%

Role of refractory elements in near-alpha titanium alloys on high temperature mechanical properties

et al. 2020

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“…Al, Sn, and Ga form the DO 19 crystal structure in binary systems of Ti-X (X = Al, Sn, Ga), i.e., Ti 3 Al in the Ti-Al system, Ti 3 Sn in the Ti-Sn system, and Ti 3 Ga in the Ti-Ga system, in addition to ternary and multicomponent systems. [9][10][11][12][13] The interaction between a 2 particles and moving dislocations, such as interactions that lead to particles shearing or bypassing dislocations, depends on the size, distribution, and volume fraction of the particles. [9] The formation of large amounts of a 2 phase leads to embrittlement.…”

Section: Introductionmentioning

confidence: 99%

“…[12] To avoid embrittlement due to the formation of the a 2 phase or ordering in multicomponent Ti alloys, the empirical Al-equivalent formula given by Al + 1/2 9 Ga + 1/3 9 Sn + 1/6 9 Zr + 10 9 O in wt pct, which is associated with the amounts of the a-stabilizing elements, has been used; the empirical Al equivalence should not exceed 9 for practical use. [12,13] Thus, controlling the amount of such a stabilizers while considering the Al equivalence is essential for enhancing strength while maintaining ductility in near-a Ti alloys.…”

Section: Introductionmentioning

confidence: 99%

Effects of Ga and Sn Additions on the Creep Strength and Oxidation Resistance of Near-α Ti Alloys

Kitashima

Yamabe‐Mitarai

Iwasaki

et al. 2016

Metall Mater Trans A

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The effects of Ga and Sn additions, with an almost constant value regarding Al equivalence, on the creep properties and oxidation resistance of the near-a Ti alloy Ti-5Al-4Zr-1Mo were investigated. The creep strain rate increased due to the replacement of Sn with Ga, which was accompanied by an increase in the volume fraction of primary equiaxed a phase. In addition, the replacement of Sn with Ga decreased the activation energy of the steady-state creep rate for the similar volume fraction of the equiaxed a phase. Ga addition improved the oxidation resistance without Ga segregation at the TiO 2 /substrate interface, whereas Sn promoted oxide spallation with metallic Sn segregation at the interface. Ga uniformly dissolved into the internal TiO 2 and into the external Al 2 O 3 as a result of solid solution formation between Ga 2 O 3 and the aforementioned oxides, which suppressed oxide growth. The formation of (GaAl) 2 TiO 5 in TiO 2 and Al 2 O 3 was also discussed on the basis of the phase relationships in the TiO 2 -Al 2 O 3 -Ga 2 O 3 system.

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“…[1][2][3][4] The previous two problems can be solved by the application of oxidation-resistant coatings on the surface of the titanium alloy. [5][6][7][8][9] These coated titanium alloys, however, can not yet work above 600°C for a reasonably long time because of the loss of plasticity due to the precipitation of undesired thermal products such as Ti 3 X or silicides.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8][9] These coated titanium alloys, however, can not yet work above 600°C for a reasonably long time because of the loss of plasticity due to the precipitation of undesired thermal products such as Ti 3 X or silicides. [1][2][3] Also, the high-temperature fatigue failure is still limiting the further wide application of the titanium alloy. [10][11][12] To promote its maximum longterm service temperature, a titanium alloy should be protected not only by the oxidation-resistant coating, but also by the thermal insulation coating.…”

Section: Introductionmentioning

confidence: 99%

Thermal failure of thermal barrier coating with thermal sprayed bond coating on titanium alloy

Zhou

et al. 2008

J Coat Technol Res

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A thermal spray technology high-velocity oxygen fuel (HVOF) was used to deposit NiCoCrAlY as a bond coating between the titanium alloy substrate and top 8 wt% yttria-stabilized zirconia thermal-barrier coating (TBC) deposited by electron beam-physical vapor deposition (EB-PVD). The thermal cycling and isothermal exposure tests were conducted to evaluate the durability of the TBC. Investigations using OM, SEM, EPMA, and XRD revealed that the thermalsprayed BC makes the TBC more durable in isothermal exposure tests but more short-lived in thermal cycling tests, in comparison to our previous study in which the BC was prepared by EB-PVD. This is because the thermal-sprayed imperfections, such as microcracks and voids, elevate the diffusion resistance and degrade the mechanical properties of the BC, simultaneously. To current TBC systems in which the BC is deposited by HVOF, thermal failure behaviors-such as the formation of the Ti/Al mixture oxides at some individual places in the BC, and the Ti 2 Ni gaps formed around the BC/substrate interface-were also discussed.

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Creep resistance and high-temperature metallurgical stability of titanium alloys containing gallium

Cited by 22 publications

References 6 publications

Role of refractory elements in near-alpha titanium alloys on high temperature mechanical properties

Role of refractory elements in near-alpha titanium alloys on high temperature mechanical properties

Effects of Ga and Sn Additions on the Creep Strength and Oxidation Resistance of Near-α Ti Alloys

Thermal failure of thermal barrier coating with thermal sprayed bond coating on titanium alloy

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