Compressive strength and creep properties of Ir-Nb-Zr alloys between 1473 and 2073 K

Yamabe‐Mitarai, Yoko; Harada, Hiroshi

doi:10.1007/s11661-003-0284-9

Cited by 17 publications

(12 citation statements)

References 16 publications

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“…[11] Shadow symbols represent composition of tested alloys. [7,18] 2073 K 24 h fcc ϩ L1 2 cuboidal L1 2 Ir-25Nb 2273 K 24 h L1 2 -single phase -Ir-12Zr [7,10,18] 2073 K 24 h fcc ϩ L1 2 discontinuous coarsening lamellae Ir-25Zr 2273 K 24 h L1 2 -single phase -Ir-13Nb-3Zr [11,12] 1773 K 24 h fcc ϩ L1 2 cuboidal L1 2 or semicoherent L1 2 Ir-9Nb-6Zr [11,12] 1773 K 24 h fcc ϩ L1 2 cuboidal L1 2 or semicoherent L1 2 Ir-4Nb-9Zr [11,12] 1773 K 24 h fcc ϩ L1 2 cuboidal L1 2 or semicoherent L1 2 ture includes high strain. Then, discontinuous coarsening occurs from grain boundaries above 1773 K, and the coarse lamellar structure covered the entire area of the sample during the heat treatment.…”

Section: A Binary Alloysmentioning

confidence: 99%

“…[11] Fine L1 2 precipitates with 100-nm size in the Ir-Nb-Zr alloy are very promising to improve the creep properties. [12] The creep behavior of the Ir-Nb-Zr alloys at 2073 K under 137 MPa is discussed and compared with those of Ir-Nb, Ir-Zr, and previously studied Ir-Nb-Ni alloys. [13,14] This applied stress, 137 MPa, was chosen for the creep testing condition because this applied stress is often used to assess Ni-base superalloys.…”

Section: Introductionmentioning

confidence: 99%

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Compressive creep properties of Ir-base refractory superalloys

Yamabe‐Mitarai

Harada

2005

Metall Mater Trans A

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Ir-base alloys with the fcc and L1 2 -Ir 3 X (X ϭ Nb, Zr) two-phase structure have been developed as next-generation high-temperature materials. The compressive creep behavior of Ir-Nb and Ir-Zr alloys was investigated at 2073 K under 137 MPa. The effect of addition of the third element, Zr, on the creep behavior of an Ir-Nb alloy was also investigated at 2073 K for 137 MPa. The creep rate became two orders lower by addition of a small amount of Zr. The lattice misfit change between the fcc and L1 2 two phase by addition of Zr and the deformation structure in binary and ternary alloys after a creep test were also investigated. The creep behavior is discussed in terms of the lattice misfit, precipitate shape, and their distribution.

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Section: A Binary Alloysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Compressive creep properties of Ir-base refractory superalloys

Yamabe‐Mitarai

Harada

2005

Metall Mater Trans A

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“…[5] By adjusting the heat-treatment conditions, the L1 2 precipitate morphology in Ir-based alloys can be controlled. [14] Heat treatment at 1773 Kr esults in coherent cuboidal L1 2 precipitates( type A) with as ize of 150 nm, and platelike fcc phases are observed. When the L1 2 precipitate was annealed at 2073 Kfor 24 hours, acoherent type Bcuboidal L1 2 precipitate of length 150 nm appeared.…”

Section: Introductionmentioning

confidence: 95%

“…As with all hightemperature materials, the strength and creep resistance of Ir-based alloys at elevated temperatures would be the primary issues to resolve. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] As shownbythe binary phasediagram of Ir-Me, [15] where Me standsfor the transition metal,Irequilibrates with most of the transition metals,forming atwo-phase fccand L1 2 structure. The L1 2 -ordered phase is an intermetallic, Ir 3 Me, and fcc phase is an Ir-based solid solution.…”

Section: Introductionmentioning

confidence: 99%

“…Annealing at 2073 Kf or 168 hours coarsened the cuboidal L1 2 precipitates into rectangular precipitates with al ength of 400 nm. Ir-based ternaries,I r-Nb-Ni and Ir-Nb-Zr, [3,4,14] and quaternaries, Ir-Nb-Ni-Al and Ir-Nb-Pt-Al, [8,9] havea lso been developed to investigate the effect of multicomponent alloying on the microstructuralc haracteristic of Ir.I tw as found that the addition of third and fourth componentsdoes not change the fcc/L1 2 structure of Ir-Nb alloys.…”

Section: Introductionmentioning

confidence: 99%

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Ir-Nb-Si ternary refractory superalloys with a three-phase Fcc/L12/silicide structure for high-temperature applications: Phase and microstructural evolution

Sha

Yamabe‐Mitarai

Harada

2006

Metall Mater Trans A

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To findanewp hase with the potential to improve the high-temperature strengtho fI r-based superalloys, thenovel idea of introducingsilicides into theIr-Nb binary wasimplemented.Hypoeutectic Ir-10Nb, eutectic Ir-16Nb, and hypereutectic Ir-25Nballoys were used as bases, and 5mol pct Si was added through the removal of Ir.X RD (XRD),s canning electron microscopy (SEM), and electronprobe microanalysis (EPMA) revealed the formation of athree-phase fcc/L1 2 /silicide microstructure in the Ir-Nb-Si ternarya fter Si addition. The type of silicide formed was dependent on heat-treated temperatures and Nb content. After heat treatment at 1750°Cand 1600°C, atie-triangle composed of fcc/L1 2 /silicide (Ir 2 Si) appeared in the Ir-10Nb-5Si and Ir-16Nb-5Si alloys; in the Ir-25Nb-5Si alloy, an L1 2 and silicide (Ir,Nb) 2 Si tie-line was observed. In the as-cast and 1300°Cheat-treated samples, the Ir-10Nb-5Si microstructure changedt oatwo-phase fcc/silicide structure, while the Ir-16Nb-5Si alloy maintained at hree-phase fcc/L1 2 /silicide structure.T he Ir-25Nb-5Si alloy,h owever,h ad the same phases as that at 1600°C. Silicides typically continuously or discontinuously distribute along the interdendritic regions or grain boundaries of the fcc or the L1 2 phase.W ith the additiono fS i, it was found that both the eutectic point and solid solubility of Nb in Ir would shift toward Ir.

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