New Phases in Ruthenium-Coating Single-Crystal Superalloys

Feng, Qiang; Nandy, T.K.; Rowland, L.J.; Tryon, B.; Banerjee, D.; Pollock, Tresa M.

doi:10.7449/2004/superalloys_2004_769_778

Cited by 10 publications

(5 citation statements)

References 18 publications

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“…Ru has been shown by Chao [29] to substitute favourably on the Ni lattice site in NiAl. However the maximum solubility of Ru in γ' is approximately 5 at% [30], hence interestingly, in the UCSX2-5Ru alloy where a SRZ was present (after both 900 and 1100°C exposures) precipitates of RuAl (akin to those identified by Feng et al [31]) could be found within the SRZ γ' matrix, as shown in Figure 14 and Figure 15. Matrix dilution precluded the precise compositional analysis by EDX of 'RuAl' precipitates formed in aluminized UCSX2-5Ru after 500h at 1100°C.…”

Section: Test Conditionsmentioning

confidence: 72%

Oxidation and Coating Evolution in Aluminized Fourth Generation Blade Alloys

Edmonds¹,

Evans²,

Jones³

2008

Superalloys 2008 (Eleventh International Symposium)

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Oxidation tests have been undertaken in air on two aluminized experimental fourth-generation Ni-based superalloys containing, respectively, 3 and 5 wt.% Ru, in order to detail the effect of Ru on oxidation characteristics and coating evolution. A Ru-free, aluminide coated third generation alloy (CMSX-10K) was also included in the test programme which used temperatures covering the range 750-1100 o C.Aluminization has been shown to effectively minimize the effect of alloy chemistry on oxidation rate constants over the timescales studied, when compared to the uncoated substrates. Aluminization also prevents the formation of internal oxidation pits in the coated Ru-bearing alloys after oxidation at 750°C. Increasing Ru marginally decreased the mass-gain due to oxidation of the three aluminized alloys at all temperatures. At 750°C the rate of oxidation of aluminized specimens was controlled not by the formation of aluminas but by that of the spinel phase Ni(Al,Cr) 2 O 4 . Interestingly, each of the three aluminized alloys produced a different coating -substrate microstructural interaction after exposure at 1100°C, with Ru increasing the propensity for secondary reaction zone (SRZ) formation. SRZs are characterized by a weak high angle boundary which can lead to localized coating loss (and hence increased section loss). Ru also underwent long range diffusion, concentrating in the β-NiAl phase in solution, and where SRZ was present resulted in the precipitation of β2-RuAl within the γ' SRZ matrix in addition to the topologically close-packed precipitates (TCPs).

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Section: Test Conditionsmentioning

confidence: 72%

Oxidation and Coating Evolution in Aluminized Fourth Generation Blade Alloys

Edmonds¹,

Evans²,

Jones³

2008

Superalloys 2008 (Eleventh International Symposium)

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“…First, Ru additions may substantially alter the thermodynamics of the superalloy system, decreasing the driving force for precipitation of undesirable phases such as the , P, and R phases. Conversely other new phases may appear in equilibrium with the and the ' phases at high temperatures; this is the subject of a companion paper in this volume [14]. If the -' phase equilibrium is modified, partitioning of elements to the phases may be altered, resulting in changes in the -' lattice misfit and precipitate morphology.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Stability and Creep of Ru-Containing Nickel-Base Superalloys

Rowland¹,

Feng²,

Pollock³

2004

Superalloys 2004 (Tenth International Symposium)

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Nickel-base single crystal superalloys with Ru additions of 5.7 to 9.7 wt%, moderate amounts of refractory elements and up to 6.7 wt% Cr were investigated. The ' precipitate morphology of the experimental alloys was cuboidal, near-spherical and intermediately-shaped depending on the Cr and Ru content. The time to 1% creep and the creep rupture lives of the experimental alloys were measured at 950°C and 290 MPa. Within the set of alloys investigated rafting occurred parallel to the axis of the applied uniaxial tensile stress, perpendicular to the applied stress or was completely suppressed, suggesting a wide range of lattice misfit. Interfacial dislocation network development during creep also varied widely among the alloys investigated. The possibilities for control of microstructure and high temperature properties via Ru additions are discussed.

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“…3. According to the SEM and TEM observation, it is judged as NiAl base b phase, which has been seldom reported except that it was found by Feng et al 15 in a single crystal superalloy with high Ru content (9?6 wt-%). In these test alloys, only in 3Ru alloy, the b phase was found, which illustrates that the a 0Ru alloy; b 1?5Ru alloy; c 3Ru alloy 1 Dendrite microstructures of alloys with different contents of Ru Differential thermal analysis DSC analysis was employed to investigate the solidification sequence and transformation temperatures in three alloys with the heating rate of 5 K min 21 .…”

Section: Resultsmentioning

confidence: 93%

Effect of Ru on microstructural evolution during heat treatment in single crystal superalloys

Liu

Jin

Liu

et al. 2014

Materials at High Temperatures

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The effect of Ru addition on the as cast microstructure, structural evolution during heat treatment and long term aging was employed in single crystal superalloys with different contents of Ru addition (0, 1?5 and 3?0 wt-%). The results show that NiAl based b phase can occur in the interdendritic region in 3Ru alloy. With increasing Ru content in the alloys, the incipient melting temperature of alloy decreases gradually, while the liquidus and solidus changed slightly. After solution treatment and the same aging treatment, the c9 phase size decreased with increasing Ru addition. An remarkable inverse partition of alloying elements, i.e. more matrix forming elements Re and Mo distribute to the c9 phase and more Ni element distribute to the matrix, was observed in the alloys with more Ru content after aging treatment. Ru addition can accelerate the rafting of c9 phase and suppress the precipitation of topologically close packed (TCP) phases effectively.

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New Phases in Ruthenium-Coating Single-Crystal Superalloys

Cited by 10 publications

References 18 publications

Oxidation and Coating Evolution in Aluminized Fourth Generation Blade Alloys

Oxidation and Coating Evolution in Aluminized Fourth Generation Blade Alloys

Microstructural Stability and Creep of Ru-Containing Nickel-Base Superalloys

Effect of Ru on microstructural evolution during heat treatment in single crystal superalloys

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