Powder Metallurgy and Oxide Dispersion Processing of Superalloys

Borofka, J. C.; Tien, J. K.

doi:10.1016/b978-0-12-690845-9.50014-2

Cited by 6 publications

(2 citation statements)

References 21 publications

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“…Powder metallurgy (P/M) technology is applied as an innovative process for the production of superalloy turbine discs from the 1970s due to the development of alloys such as Rene 95, Astroloy, and MERL 76, which were found not to be amenable to being processed into traditional cast-and-wrought forms. The advantages of P/M processing include improved property uniformity due to the elimination of macro-segregation and the development of a fine grain size [3,4]. The P/M nickel-base superalloy, FGH4096, is regarded as one of the most promising powder metallurgy superalloy for high-temperature and high-pressure turbine disc in aerospace industries for its high crack resistance, high strength, and high working temperature of up to 750 °C [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Effect of Hot Extrusion on the Flow Behaviour of a Nickel-Based P/M Superalloy

Yang

Liu

Chen

2019

SSP

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This research investigated the effect of hot extrusion on the flow behaviour of nickel-based superalloy FGH4096 by hot compression experiments in the temperature range from 1020 to 1110 °C and strain rates ranging from 0.1 to 0.001 s-1. The influence of the hot extrusion on the initial microstructures, work hardening rate, strain rate sensitivity, and activation energy of deformation were discussed. The results show that the extruded microstructure is constituted by the fine dynamic recrystallisation of grains. The true strain-true stress curves show that the as-HIPed and as-HEXed FGH4096 superalloy present double flow stress peaks and discontinuous flow softening. The as-HEXed FGH4096 is easily dynamically softened at high temperatures and high strain rates compared with as-HIPed microstructures. As for the work hardening rate, the as-HEXed FGH4096 exhibits higher θ values than that of as-HIPed. It is beneficial to the homogenous deformation and grain refinement during subsequent turbine disk forging. Comparing to as-HIPed FGH4096, the highest strain rate sensitivity value of as-HEXed is 0.306 at 1110 °C. The isothermal superplastic forging of a P/M turbine disk may be carried out at this temperature. The deformation activation energy value of the as-HIPed FGH4096 is lower which means that dislocation sliding and climbing can be easily initiated in the as-HIPed alloy.

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Section: Introductionmentioning

confidence: 99%

Effect of Hot Extrusion on the Flow Behaviour of a Nickel-Based P/M Superalloy

Yang

Liu

Chen

2019

SSP

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“…Alloys such as waspaloy and IN718 are generally prepared by ingot metallurgy, since the levels of strengthening elements Al, Ti, W and Mo are relatively low. Unfortunately, C&W route can not be applied to the heavily alloyed refractory superalloys such as Rene 95 [3] and Rene 88DT [4] , since the high levels of segregation generated during solidification process cause the tendency to cracking during hot working; instead, P/W route is preferred, despite the disadvantages of high cost, long process and difficulty of preparing powder without inclusions [5] .…”

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confidence: 99%

Microstructure and Segregation Behavior of Rene88DT Alloy Prepared by ESR-CDS

Feng

et al. 2016

Rare Metal Materials and Engineering

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Directionally solidified Rene88DT alloy ingots were produced by electroslag remelting continuous directional solidification (ESR-CDS) technology. The as-cast structures of ESR-CDS Rene88DT alloy ingot were analyzed by optical microscopy (OM), field emission scanning electron microscopy (FESEM) with energy spectrum and transmission electron microscopy(TEM), and simultaneously compared with conventional ESR ingot. The results show that the region of the severe central segregation existing commonly in the conventional ESR ingot is eliminated in the ESR-CDS Rene88DT alloy ingot, because the above segregation is formed in the intersection of interfaces among columnar crystals and equiaxed crystals or between columnar crystals each other. In addition, the ESR-CDS Rene88DT alloy ingot shows smaller secondary dendritic spacing and smaller non-equilibrium precipitates phase. Due to the decreasing micro-segregation level, the uniform distribution of alloy elements can be achieved when Rene 88DT alloy is subjected to the heat treatment at 1200 o C for 24 h. Statistical results of inclusions reveal that the maximum size of inclusion in the ESR-CDS Rene88DT alloy is not more than 5.89 μm and the inclusion volume reduces by over 60% compared with conventional ESR and P/M, respectively. The hot working plasticity of directionally solidified Rene88DT superalloy can be improved, which provides a basis for implementation of cast-and-wrought (C&W) route.

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14 Intermetallic materials

Sauthoff¹

Powder Metallurgy Data. Refractory, Hard and Intermetallic Materials

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Powder Metallurgy and Oxide Dispersion Processing of Superalloys

Cited by 6 publications

References 21 publications

Effect of Hot Extrusion on the Flow Behaviour of a Nickel-Based P/M Superalloy

Effect of Hot Extrusion on the Flow Behaviour of a Nickel-Based P/M Superalloy

Microstructure and Segregation Behavior of Rene88DT Alloy Prepared by ESR-CDS

14 Intermetallic materials

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