Phase-Field Simulation of the Effect of Elastic Inhomogeneity on Microstructure Evolution in Ni-Based Superalloys

Tsukada, Yuhki; Murata, Yoshinori; Koyama, Toshiyuki; Morinaga, Masahiko

doi:10.2320/matertrans.mbw200826

Cited by 25 publications

(10 citation statements)

References 13 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: 73%

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: 73%

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

et al. 2018

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“…These effects have been studied extensively for diffusion-controlled phase transformations. [4][5][6] Recently, simulation studies of martensitic transformations focussing on effects of elastic properties have also been made. [5][6][7][8][9][10] The elastic moduli of iron-carbon martensite were reported by several researchers.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6] Recently, simulation studies of martensitic transformations focussing on effects of elastic properties have also been made. [5][6][7][8][9][10] The elastic moduli of iron-carbon martensite were reported by several researchers. [11][12][13][14][15] Schmidtmann et al 11) measured Young's modulus of quenched carbon steels by the resonance vibration method and found that it decreases with increasing the C content.…”

Section: Introductionmentioning

confidence: 99%

Elastic Properties of Fe–C and Fe–N Martensites

Souissi

Numakura

2015

ISIJ International

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Single-crystal elastic constants of bcc iron and bct Fe-C and Fe-N alloys (martensites) have been evaluated by ab initio calculations based on the density-functional theory. The energy of a strained crystal has been computed using the supercell method at several values of the strain intensity, and the stiffness coefficient has been determined from the slope of the energy versus square-of-strain relation. Some of the third-order elastic constants have also been evaluated. The absolute magnitudes of the calculated values for bcc iron are in fair agreement with experiment, including the third-order constants, although the computed elastic anisotropy is much weaker than measured. The tetragonally distorted dilute Fe-C and Fe-N alloys exhibit lower stiffness than bcc iron, particularly in the tensor component C 33 , while the elastic anisotropy is virtually the same. Average values of elastic moduli for polycrystalline aggregates are also computed. Young's modulus and the rigidity modulus, as well as the bulk modulus, are decreased by about 10% by the addition of C or N to 3.7 atomic per cent, which agrees with the experimental data for Fe-C martensite.

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“…Although it is difficult to examine experimentally the effect of elastic inhomogeneity on microstructure formation, it may have a significant impact, and it can be examined by phase field simulation. In fact, it has been reported that a large elastic inhomogeneity can affect microstructural evolution, yielding a significantly different microstructure to that of an elastically homogeneous system [19][20][21][22][23][24][25][26]. Phase-field simulations of the formation of c/c 0 microstructure in Ni-based superalloy, with the effect of elastic inhomogeneity taken into account, have been already conducted [27,28], and it was shown that there was little effect of elastic inhomogeneity on the morphology of microstructure formed under no applied stress.…”

Section: Introductionmentioning

confidence: 95%

Mechanisms of lamellar structure formation and Cr interfacial segregation in C11b-MoSi2/C40-NbSi2 dual phase silicide verified by a phase-field simulation incorporating elastic inhomogeneity

Yamazaki

Koizumi

Yuge

et al. 2015

Computational Materials Science

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a b s t r a c tWe developed a phase-field model of C11 b -MoSi 2 /C40-NbSi 2 duplex silicide incorporating elastic inhomogeneity, and simulated microstructure formation and interface segregation. We examined the effect of elastic inhomogeneity on the morphology, volume fraction of the C11 b -precipitate, stress distribution, and solute partitioning. In the simulations, parameters evaluated by first-principles calculation are used for the experimentally unknown parameters. The lamellar structure was not formed in the case incorporating the elastic strain energy only and ignoring the anisotropy of the interfacial energy. When the anisotropy of the interfacial energy was taken into account, the lamellar structure was formed parallel to (0 0 0 1) C40 as observed in the experiment. It was also found that the elastic strain energy changes the equilibrium concentrations by >0.2 at%, but the difference between the equilibrium concentrations in homogeneous and inhomogeneous systems was <0.1 at%. The interfacial segregation was also hardly affected by the elastic inhomogeneity. These results confirm that elastic inhomogeneity can be neglected in the simulation of MoSi 2 /NbSi 2 lamellar silicide.

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Phase-Field Simulation of the Effect of Elastic Inhomogeneity on Microstructure Evolution in Ni-Based Superalloys

Cited by 25 publications

References 13 publications

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

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

Elastic Properties of Fe–C and Fe–N Martensites

Mechanisms of lamellar structure formation and Cr interfacial segregation in C11b-MoSi2/C40-NbSi2 dual phase silicide verified by a phase-field simulation incorporating elastic inhomogeneity

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