Theoretical and experimental investigations on elastic interactions between ??-precipitates in a Ni-Al alloy

Miyazaki, Tôru; Imamura, Hiroshi; Mori, Hirotarô; Kozakal, T.

doi:10.1007/bf01033832

Cited by 60 publications

(5 citation statements)

References 11 publications

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“…Thus, coalescence of neighboring ordered γ ' particles is difficult and rarely observed. This so-called discontinuous rafting microstructure has been observed in commercial Ni-based superalloys [35][36][37][38][39][40]. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 10…”

Section: Microstructural Evolution At 900°cmentioning

confidence: 72%

Kinetics pathway of precipitation in model Co-Al-W superalloy

et al. 2018

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Abstract:The early stages of precipitation of the γ ' phase in a model Co based superalloy (Co-9.1Al-7W (at.%)) have been investigated at 900 °C using electron microscopy and atom probe tomography. Nucleation, growth and coarsening stages have been studied with a focus on the temporal evolution of the precipitate composition in the light of recent theoretical developments on phase separation in multicomponent alloys. The experimental data have been confronted to the theories of nucleation and coarsening recently developed for such alloys, which are valid for non-ideal and non-dilute systems, and predict the temporal evolution of both the matrix and precipitate compositions. The rate constant for the mean size evolution of the particles, as derived from experiments, has been compared to the one predicted by the mentioned coarsening theory that accounts for a more accurate description of the thermodynamics of the phases, as compared with more classical approaches. From this comparison the γ/γ' interfacial energy was derived and found equal to ~48 mJ/m 2 . the exponents for the temporal evolution of average particles size, number of particles per unit volume were found identical to those for binary alloys during the coarsening regime, as expected, and the temporal evolutions of compositions in both γ and γ' phases were found to evolve as predicted by theory. Indeed, the W content in the particles, measured from atom probe tomography (APT) experiments, was found to significantly decrease with time and the observed evolution is remarkably well described by the theory and therefore is shown to originate from the competition between diffusion and capillarity.

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Section: Microstructural Evolution At 900°cmentioning

confidence: 72%

Kinetics pathway of precipitation in model Co-Al-W superalloy

et al. 2018

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“…Depending on the cooling rate, the shape of these particles varies over a wide range, from simple spheres over cubes and octocubes to complex structures, such as octodendrites and dendrites. This large variety of dissimilar morphologies [1][2][3][4][5][6][7][8][9][10][11][12] caused by the c/c 0 lattice mismatch [13] is well known.…”

Section: Introductionmentioning

confidence: 99%

Multimodal size distributions of γ′ precipitates during continuous cooling of UDIMET 720 Li

et al. 2009

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“…The elastic interaction energy Eint originates from the overlap of the elastic strain fields around the individual coherent particles. An important feature of elastic interaction energy is that it has a negative minimum when the two particles are adjacent to each other along <loo> directions (13). Ardell,Nicholson and Shelby (14) proposed an idea about the precipitate distribution.…”

Section: Introductionmentioning

confidence: 99%

Effect of Elastic Interaction Energy on the Distribution of Coherent Precipitate Particles in Nickel-Base Alloys

Doi¹,

Miyazaki²

1992

Superalloys 1992 (Seventh International Symposium)

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Two new parameters which can numerically describe the precipitate distribution are proposed. One is for the directional alignment along [/r/V] direction and is symbolized by 'Plhk,. The other is for the non-uniform (localized) distribution and is symbolized by A. By using the parameters, the sequence of morphological change of coherent precipitates under the influence of elastic interaction energy in Ni-base alloys are analyzed and the following conclusions are obtained: (1) as coarsening proceeds, the alignment along starts, then the localization also starts, (2) after non-uniform (localized) distribution of particles which are aligned along is attained, the particle sizes become uniform, (3) the retardation of coarsening takes place.

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Theoretical and experimental investigations on elastic interactions between ??-precipitates in a Ni-Al alloy

Cited by 60 publications

References 11 publications

Kinetics pathway of precipitation in model Co-Al-W superalloy

Kinetics pathway of precipitation in model Co-Al-W superalloy

Multimodal size distributions of γ′ precipitates during continuous cooling of UDIMET 720 Li

Effect of Elastic Interaction Energy on the Distribution of Coherent Precipitate Particles in Nickel-Base Alloys

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