Development and application of nickel alloys in aerospace engineering

Smith, Richard J.; Lewi, G.J.; Yates, D.H.

doi:10.1108/00022660110694995

Cited by 67 publications

(27 citation statements)

References 1 publication

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“…[2] at large strains, and deviations from it are observed only at lower strains. The deviation at lower strains is thought to correspond to the regime of planar glide of dislocations against cross-slip of dislocations at large strains.…”

Section: B Strain Hardening and Plastic Flowmentioning

confidence: 80%

“…A linear relationship should be observable on a plot of ln r vs ln e if Eq. [2] adequately describes the flow behavior. However, in the case of alloy 720Li, this is not so at 25°C and 400°C as could be seen from the typical ln r vs ln e plot in Figure 12.…”

Section: B Strain Hardening and Plastic Flowmentioning

confidence: 98%

“…It can be observed from Table II that values of n 1 are at least an order of magnitude lower than n 2 and values of n 2 at 25°C are closer to the values obtained for n (as in Eq. [2]) for many engineering alloys. [14,15] Therefore, n 2 , which represents the strain hardening behavior at larger strains well beyond the S Y , is considered the Strain hardening is a result of reduced dislocation mobility generally due to (a) interaction between stress fields of dislocations, (b) formation of sessile dislocation locks, and (c) formation of jogs on dislocations due to interpenetration of slip systems.…”

Section: B Strain Hardening and Plastic Flowmentioning

confidence: 99%

“…Because of the high alloying element content, initially, alloy 720Li could be processed for turbine disc applications only through powder metallurgy route. [1,2] However, with optimization of melting processes and improved process control during metal working, processing of alloy 720Li through ingot metallurgy (cast and wrought) route is now possible and commercially viable. Hence, alloy 720Li is now considered to be one of the most advanced disc alloys to be processed through the cast and wrought route [3] for service temperatures in the range of 650°C to 730°C.…”

Section: Introductionmentioning

confidence: 99%

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Tensile Properties of Ni-Based Superalloy 720Li: Temperature and Strain Rate Effects

Gopinath

Gogia

Kamat

et al. 2008

Metall Mater Trans A

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Tensile properties, deformation, and fracture behavior of a wrought nickel-base superalloy 720Li have been studied in standard solutionized and two-stage-aged condition in the temperature range of 25°C to 750°C. Effect of strain rate on tensile behavior was assessed at 25°C, 400°C, and 750°C at five strain rates that range between 10 -5 s -1 and 10 -1 s -1 . The yield strength and ultimate tensile strength of the alloy remained unaffected by temperature until about 600°C and 500°C, respectively, typical of superalloys strengthened by fine and coherent intermetallic Ni 3 Al-based precipitates. The flow stress of the alloy was found to be insensitive to the strain rates studied at 25°C and 400°C. However, at 750°C, the flow stresses showed strain rate sensitivity at strain rates <10 -3 s -1 . The strain hardening behavior at 25°C and 400°C were similar. At 750°C, stain hardening was observed only at strain rates >10 -3 s -1 , and at lower strain rates, tensile instability was seen to set in immediately after yielding. The alloy exhibited ductile dimple fracture at all the temperatures and strain rates studied. Microstructural investigations indicate that in regimes where flow stresses are insensitive to strain rate, deformation occurs through heterogeneous planar slip, whereas in strain rate sensitive regimes, thermally activated diffusion processes promote homogeneous deformation.

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Section: B Strain Hardening and Plastic Flowmentioning

confidence: 80%

Section: B Strain Hardening and Plastic Flowmentioning

confidence: 98%

Section: B Strain Hardening and Plastic Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tensile Properties of Ni-Based Superalloy 720Li: Temperature and Strain Rate Effects

Gopinath

Gogia

Kamat

et al. 2008

Metall Mater Trans A

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“…Moreover, using SPF, it is possible to produce complex shapes without the need for welding or riveting operations [2]. While historically SPF has been first used for aerospace alloys such as titanium alloys and high strength aluminum alloys, its application to other alloys is continuously increasing [3].…”

Section: Introductionmentioning

confidence: 99%

Influence of predeformation on microstructure evolution of superplastically formed Al 5083 alloy

Chentouf

Belhadj

Bombardier³

et al. 2016

Int J Adv Manuf Technol

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Cavitation is the main defect encountered during superplastic forming (SPF) of thin sheet aluminum alloys. In the present paper, the influence of preforming operation (cold or hot) on the superplastic forming ability and quality of 1.6-mm-thick sheet of 5083 SPF aluminum alloy is investigated. Specifically, grain size evolution and the characteristics of the cavitation process are discussed as a function of prior deformation and the preforming temperature. Optical and field emission gun scanning electron microscopy (FEG-SEM) were used to study the characteristics of the cavities and microstructure evolution. Image processing was used to measure the surface and volume fractions of the cavities. The results indicate that hot preforming leads to a lower number of cavities per unit surface compared to cold preforming prior to the SPF operation. However, the average cavity sizes and the average grain size are higher in the case of hot preforming compared to cold preforming, which lead to higher susceptibility to crack formation and reduced SPF ability of the alloy.

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Hot Deep Drawing Processing of Titanium Sheet Metal Parts for High Temperature Applications

et al. 2018

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Hot deep drawing (HDD) is an innovative promising compromise to reduce costs by saving production time and to reduce the expenses for surface treatment. Parts made by HDD provide a high accuracy and constant wall thickness suitable for automated industrial assembly. In this paper, the behavior of one near-α titanium alloy, used to manufacture the components of exhaust systems, are observed during HDD. It aims at improving the mechanical properties of the formed component by means of an integrated annealing to prevent, or at least minimize, the spring back behavior. For this purpose, the parameters of HDD followed by the so-called creep relaxation period are optimized. They are: heating time, forming temperature, creep strain, strain rate, and relaxation time. Based on a statistical experimental design, the experimental procedure are conducted by utilizing a forming dilatometer. The results reveal a considerable impact of relaxation time on the material behavior. In addition, variation of the strain rate has also an effect on the considered outputs. Regarding the aforementioned challenges, a set of parameter is suggested, with which all the expected drawbacks can be diminished.

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Development and application of nickel alloys in aerospace engineering

Cited by 67 publications

References 1 publication

Tensile Properties of Ni-Based Superalloy 720Li: Temperature and Strain Rate Effects

Tensile Properties of Ni-Based Superalloy 720Li: Temperature and Strain Rate Effects

Influence of predeformation on microstructure evolution of superplastically formed Al 5083 alloy

Hot Deep Drawing Processing of Titanium Sheet Metal Parts for High Temperature Applications

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