Mechanism of competitive grain growth in directional solidification of a nickel-base superalloy

Zhou, Yizhou; Volek, Andreas; Green, Nick

doi:10.1016/j.actamat.2008.02.022

Cited by 143 publications

(94 citation statements)

References 9 publications

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“…In the previous work [8], we have reported that the thermal gradient of the casting system is not the reason why the misaligned dendrites are able to overgrow the better aligned dendrites, i.e. the overgrowth process is not due to the inclination of the thermal gradient with respect to the withdrawal direction.…”

Section: Overgrowth Of Converging Grains and Dendritesmentioning

confidence: 99%

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Competitive Grain Growth in Directional Solidification of a Nickel-Base Superalloy

Zhou¹,

Green²

2008

Superalloys 2008 (Eleventh International Symposium)

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The structure evolution of bi-crystal samples during directional solidification was explored. It was found that in the case of diverging dendrites the better aligned grains overgrew the misaligned grains by means of the dendrite development from the better aligned grains. However, in the case of converging dendrites the result differs in two ways from the prediction of the generally accepted model for competitive grain growth. First, the misaligned dendrites are able to overgrow the better aligned dendrites. Second, the misaligned grains are able to overgrow the better aligned grain by blocking the dendrites of the better aligned grains at the grain boundary. The results can explain the potential sources of misorientation defects in seeded single crystal components and can be used to optimize process design to eliminate the stray grain defects in seeded single crystal casting.

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Section: Overgrowth Of Converging Grains and Dendritesmentioning

confidence: 99%

“…In our work [8], structure evolution of bi-crystal (BC) samples during the DS process was explored in an attempt to understand the mechanism of competitive grain growth. It was found that in the case of diverging dendrites the best aligned grain overgrew the misaligned grain.…”

Section: Introductionmentioning

confidence: 99%

Competitive Grain Growth in Directional Solidification of a Nickel-Base Superalloy

Zhou¹,

Green²

2008

Superalloys 2008 (Eleventh International Symposium)

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“…At a converging grain boundary, misaligned dendrites are thus slightly behind those of the well-aligned grain and the boundary is locked. However, Zhou et al [33] have shown in a bicrystal Ni-base superalloy that such is not strictly the case. The solutal interaction between two converging neighboring dendrite tips slows them both down.…”

Section: Stochastic Grain Structure Modelsmentioning

confidence: 99%

Modeling and characterization of grain structures and defects in solidification

Rappaz

2016

Current Opinion in Solid State and Materials Science

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a b s t r a c tThe paper by Karma and Tourret (this volume) in this special issue focuses on multiscale modeling approaches ranging from atoms to microstructure. In the present one, the most recent and significant modeling contributions dealing with the scale of solidification from microstructure to grain structure are briefly reviewed. The paper also covers modeling of defect formation during the last stage of solidification, namely porosity and hot tearing. As will be shown, the field of solidification has taken advantage of several simulation and experimental tools which have become increasingly powerful and accessible over the past decade. The emphasis will be put on complex 2D and 3D models for which correlations with in situ observations using synchrotron radiation and/or combined orientation and metallography imaging have been made.

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“…16,93,94 On the other hand, unusual dendrite selections, in which inclined dendrites overgrow dendrites growing in the heat flow direction, have recently been observed in the unidirectional solidification of a bicrystal sample. 95,96 To clarify the mechanism of this unusual overgrowth, two-dimensional phase-field simulations have been performed. 34,36,90 In the following subsections, we .…”

Section: High-performance Computation For the Phase-field Methodsmentioning

confidence: 99%

Solidification in a Supercomputer: From Crystal Nuclei to Dendrite Assemblages

Shibuta

Ohno

Takaki

2015

JOM

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Thanks to the recent progress in high-performance computational environments, the range of applications of computational metallurgy is expanding rapidly. In this paper, cutting-edge simulations of solidification from atomic to microstructural levels performed on a graphics processing unit (GPU) architecture are introduced with a brief introduction to advances in computational studies on solidification. In particular, million-atom molecular dynamics simulations captured the spontaneous evolution of anisotropy in a solid nucleus in an undercooled melt and homogeneous nucleation without any inducing factor, which is followed by grain growth. At the microstructural level, the quantitative phase-field model has been gaining importance as a powerful tool for predicting solidification microstructures. In this paper, the convergence behavior of simulation results obtained with this model is discussed, in detail. Such convergence ensures the reliability of results of phase-field simulations. Using the quantitative phase-field model, the competitive growth of dendrite assemblages during the directional solidification of a binary alloy bicrystal at the millimeter scale is examined by performing two-and threedimensional large-scale simulations by multi-GPU computation on the supercomputer, TSUBAME2.5. This cutting-edge approach using a GPU supercomputer is opening a new phase in computational metallurgy.

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Mechanism of competitive grain growth in directional solidification of a nickel-base superalloy

Cited by 143 publications

References 9 publications

Competitive Grain Growth in Directional Solidification of a Nickel-Base Superalloy

Competitive Grain Growth in Directional Solidification of a Nickel-Base Superalloy

Modeling and characterization of grain structures and defects in solidification

Solidification in a Supercomputer: From Crystal Nuclei to Dendrite Assemblages

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