High-temperature strength and room-temperature toughness of Nb–W–Si–B alloys prepared by arc-melting

Sha, Jiangbo; Hirai, Hisatoshi; Tabaru, Tatsuo; Kitahara, Akira; Ueno, Hidetoshi; Hanada, Shuji

doi:10.1016/j.msea.2003.08.014

Cited by 73 publications

(35 citation statements)

References 21 publications

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“…Crack propagation behavior is shown to propagate straight in eutectic and along interface between primary and eutectic phase [9]. The SEM fractography in Fig.…”

Section: Discussionmentioning

confidence: 90%

Effect of Gallium on microstructure and mechanical properties of Nb–Si eutectic alloy

Kashyap

Tiwary

2011

Intermetallics

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“…Crack propagation behavior is shown to propagate straight in eutectic and along interface between primary and eutectic phase [9]. The SEM fractography in Fig.…”

Section: Discussionmentioning

confidence: 90%

Effect of Gallium on microstructure and mechanical properties of Nb–Si eutectic alloy

Kashyap

Tiwary

2011

Intermetallics

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“…Most of the research so far has been focused on Mo-Si-B alloys [1,2] even though some investigations have also evaluated related systems. [3][4][5] In terms of the current knowledge of phase equilibria concerning the Nb-B, Nb-Si and Si-B binary systems, the following information should be mentioned: Borges Jr. et al [6] have reevaluated the Nb-rich region (0-50 at.% B) of the Nb-B system and reported important discrepancies with respect to the phase diagram shown in, [7] with their proposed phase relations being close to those from Rudy et al [8] In fact, Rudy's diagram lacks only the Nb 5 B 6 phase found by Bolmgren and Lundstrom. [9] Solidus temperatures in the Nb-B system are expected to be higher than approximately 2050°C for alloys containing up to 66.7 at.% B and at 1700°C the following solid phases should be stable: Nb ss (ss-solid solution), Nb 3 B 2 , NbB, Nb 5 B 6 , Nb 3 B 4 , NbB 2 and bB.…”

Section: Introductionmentioning

confidence: 99%

Isothermal Section of the Nb-Si-B System at 1700 °C in the Nb-NbSi2-NbB2 Region

Nunes

Júnior

Coelho

et al. 2011

J. Phase Equilib. Diffus.

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Me-Si-B (Me-metal) alloy systems have been evaluated to aid the development of ultra high temperature structural materials. In the present work, the phase relations at 1700°C in the Nb-NbSi 2 -NbB 2 region of the Nb-Si-B system have been experimentally determined. The alloys were prepared via arc melting and powder metallurgy routes. All samples were characterized via scanning electron microscopy (SEM) and x-ray diffraction (XRD) and selected samples were also scanned via wave-length dispersive spectroscopy (WDS). The high B solubility in the aNb 5 Si 3 phase has been confirmed with solubility range larger than that proposed in the 1600°C isothermal section of Nowotny et al. (Aufbau und Zunderverhalten von Niob-Bor-SiliciumLegierungen, Mon. Chem., 1960, 91, p 975-990). In contrast to Nowotny's isothermal section, it has been observed that the D8 8 -phase should be nearly stoichiometric with composition close to 57Nb35Si8B (at.%). It was also found that the D8 8 -phase does not equilibrate with NbB 2 -phase at 1700°C. A negligible Si solubility in the boride phases as well as that of B in NbSi 2 has been noticed.

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“…The microstructure composed of ad uctile (fcc/L1 2 )m atrix and ab rittle (silicide)r einforcement phase looks like ac omposite in which as ilicide with high hardness [20] contributes to the alloy's high-temperature strengtha nd plays the role of the Nb/Si silicide in Nb-Si-based alloys. [21][22][23][24][25] As is characteristic with composites, interface problemsb etweent he ductile and brittle phases, such as interface strength and inconsistent deformation, may play an important role in the hightemperature behaviors. Overcoming these problems will be the focus or our future work.…”

Section: Ivdiscussionmentioning

confidence: 99%

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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High-temperature strength and room-temperature toughness of Nb–W–Si–B alloys prepared by arc-melting

Cited by 73 publications

References 21 publications

Effect of Gallium on microstructure and mechanical properties of Nb–Si eutectic alloy

Effect of Gallium on microstructure and mechanical properties of Nb–Si eutectic alloy

Isothermal Section of the Nb-Si-B System at 1700 °C in the Nb-NbSi2-NbB2 Region

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

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