On the Effect of Nb on the Microstructure and Properties of Next Generation Polycrystalline Powder Metallurgy Ni-Based Superalloys

Christofidou, Katerina A.; Hardy, Mark; Li, Hang Yue; Argyrakis, C.; Kitaguchi, Hiroto; Jones, Nicholas; Mignanelli, P. M.; Wilson, Alison; Messé, O.M.D.M.; Pickering, Ed; Gilbert, R.J.C.; Rae, C.M.F.; Yu, Simon Chun‐Ho; Evans, Anna; Child, D. J.; Bowen, P.; Stone, Howard J.

doi:10.1007/s11661-018-4682-4

Cited by 41 publications

(18 citation statements)

References 37 publications

(46 reference statements)

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“…pct. Unexpectedly good oxidation resistance was reported recently by Christofidou et al, [18] however, for alloys A and B in Table I. While evidence was not presented to explain the behavior, it was attributed to the beneficial contributions of Ta and Co. Tantalum may form protective spinel oxides or assist in establishing a protective chromia scale.…”

Section: G Other Considerations: Phase Stability Versus Environmental Protectionmentioning

confidence: 80%

“…The details for material manufacture and testing are provided elsewhere. [18] It is understood that improved values of yield stress are due to the higher volume fraction of c¢ and the addition of Nb, which increases in APB energy. The predicted values of yield stress are particularly sensitive to the APB energy, the c grain size, the volume fraction and size of secondary c¢ precipitates, and the volume fraction of tertiary c¢ precipitates.…”

Section: B Predicting Yield Strengthmentioning

confidence: 99%

“…The APB energy pre-exponent term C o (Eq. (3) in Appendix) for each alloy was calculated from the method proposed by Crudden et al, [13] using first principle density functional theory (DFT) calculations for ternary systems comprising of Ni 0.75 Al 0.125 X 0.125 and Ni 3 Al 0.5 X 0.5 where X is an alternative c¢ former element such as Ti, Ta, Nb, or W. In an earlier publication, [18] the model was fitted to measured yield stress values at room temperature by modifying APB energy, which is calculated at zero Kelvin.…”

Section: B Predicting Yield Strengthmentioning

confidence: 99%

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Solving Recent Challenges for Wrought Ni-Base Superalloys

Hardy

Detrois

McDevitt

et al. 2020

Metall Mater Trans A

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This paper reviews the status of technology in design and manufacture of new wrought polycrystalline Ni-base superalloys for critical engineering applications. There is a strong motivation to develop new alloys that are capable of operating at higher temperatures to realize improvements in thermal efficiency, which are necessary to achieve environmental targets for reduced emissions of harmful green-house gases. From the aerospace sector, the development of new powder metallurgy and ingot metallurgy alloys is discussed for disk rotor and static applications. New compositions for powder metallurgy contain about 50 to 55 pct of gamma prime (c¢) strengthening precipitates to ensure components operate successfully at temperatures up to 788°C (1450°F). In contrast, new compositions for ingot metallurgy aim to occupy a design space in temperature capability between Alloy 718 and current powder alloys that are in-service, and show levels of c¢ of about 30 to 44 pct. The focus in developing these alloys was design for manufacturability. To complement the aerospace developments, a review of work to understand the suitability of candidate alloys for multiple applications in Advanced-Ultra Supercritical (AUSC) power plants has been undertaken by Detrois, Jablonski, and Hawk from the National Energy Technology Laboratory. In these power plants, steam temperatures are required to reach 700°C to 760°C. The common thread is to develop alloys that demonstrate a combination of high-temperature properties, which are reliant on both the alloy composition and microstructure and can be produced readily at the right price. For the AUSC applications, the emphasis is on high-temperature strength, long-term creep life, phase stability, oxidation resistance, and robust welding for fabrications. Whereas for powder disk rotors in aircraft engines, the priority is enhanced resistance to time-dependent crack growth, phase stability, and resistance to environmental damage, while extending the current strength levels, which are shown by existing alloys, to higher temperatures.

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Section: G Other Considerations: Phase Stability Versus Environmental Protectionmentioning

confidence: 80%

Section: B Predicting Yield Strengthmentioning

confidence: 99%

Section: B Predicting Yield Strengthmentioning

confidence: 99%

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Solving Recent Challenges for Wrought Ni-Base Superalloys

Hardy

Detrois

McDevitt

et al. 2020

Metall Mater Trans A

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“…Furthermore, Nb substituting onto the Al sublattice increased the anti-phase boundary (APB) energy of the γ′ phase [ 14 , 15 ], further contributing to the strength. Recently, Christofidou et al [ 16 ] studied the effect of Nb on the oxidation behavior and mechanical properties of next generation polycrystalline PM nickel-based superalloys, finding that Nb increased the volume fraction of γ′ precipitates, which could lead to superior oxidation resistance as well as high tensile and creep properties. Nevertheless, high Nb concentrations have been related to the precipitate of the η (Ni 3 Ti) and δ (Ni 3 Nb) phases, as well as the formation of σ phase, which are generally considered deleterious to mechanical properties [ 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Nb on Microstructure and Mechanical Property of Novel Powder Metallurgy Superalloys during Long-Term Thermal Exposure

Zhou

Teng

et al. 2021

Materials

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Microstructure and mechanical properties of novel Ni-20Co-12Cr superalloys, with and without Nb addition, were systematically studied during long-term thermal exposure. With increased exposure time, the average diameter of the γ′ precipitates increased in both alloys in succession; this is more obviously observed in alloy containing 1 wt% Nb (1Nb). It is suggested that Nb increased the γ′ coarsening rate by accelerating the diffusion of Al and Nb in γ matrix. In addition, the γ′ phase fraction is increased by about 4% in 1Nb compared to the alloy without Nb (0Nb). The morphology of the γ′ phase changed from near-spherical to cuboidal shape during exposure in both alloys. Due to the increased γ/γ′ lattice misfit by Nb addition, 1Nb alloy showed an earlier tendency of shape change. Vickers hardness results revealed that the overall hardness decreased with the exposure time because the size increment of the γ′ precipitate weakened the precipitates strengthening and Orowan strengthening.

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“…Therefore, there were great efforts on the Supplemental data for this article can be accessed here. https://doi.org/10.1080/21663831.2020.1815093 composition design of superalloys over the past decades [8,9]. The phases of the Ni-base superalloys generally include γ matrix, γ phase, topologically close-packed (TCP) phases, and geometrically close-packed (GCP) phases [10,11].…”

Section: Introductionmentioning

confidence: 99%

Phase prediction of Ni-base superalloys via high-throughput experiments and machine learning

Qin

Wang

et al. 2020

Materials Research Letters

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Predicting the phase precipitation of multicomponent alloys, especially the Ni-base superalloys, is a difficult task. In this work, we introduced a dependable and efficient way to establish the relationship between composition and detrimental phases in Ni-base superalloys, by integrating high throughput experiments and machine learning algorithms. 8371 sets of data about composition and phase information were obtained rapidly, and analyzed by machine learning to establish a high-confidence phase prediction model. Compared with the traditional methods, the proposed approach has remarkable advantage in acquiring and analyzing the experimental data, which can also be applied to other multicomponent alloys. IMPACT STATEMENT By integrating the high throughput experiments and machine learning algorithms, it is hopeful to facilitate the design of new Ni-base superalloys, and even other multicomponent alloys.

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On the Effect of Nb on the Microstructure and Properties of Next Generation Polycrystalline Powder Metallurgy Ni-Based Superalloys

Cited by 41 publications

References 37 publications

Solving Recent Challenges for Wrought Ni-Base Superalloys

Solving Recent Challenges for Wrought Ni-Base Superalloys

Effect of Nb on Microstructure and Mechanical Property of Novel Powder Metallurgy Superalloys during Long-Term Thermal Exposure

Phase prediction of Ni-base superalloys via high-throughput experiments and machine learning

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