Simplicity in protective relaying

Hunt, Lloyd F.

doi:10.1109/ee.1946.6440020

Cited by 2 publications

(4 citation statements)

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“…For epitaxial growth of columnar grains to be maintained, the total fraction of equiaxed SGs ϕ has to be less than a critical ϕ c (0.66%). Based on Hunt's [ 30 ] work on the SG formation mechanism, Gäumann et al [ 10 ] proposed a criterion for predicting CET transition possibility in the E‐LMF process. In terms of temperature gradient G and solidification rate V , the criterion can be formulated as

\frac{G^{n}}{V} > K_{CET}

K_{CET} = a {(\sqrt[3]{\frac{- 4 π N_{0}}{3 ln false(1 - ϕ false)}} \frac{1}{n + 1})}^{n}

in which a and n are material‐related constants.…”

Section: Epitaxial Growth Mechanism In Am Processesmentioning

confidence: 99%

“…A, B, and C represent three different laser surface remelting cases for which the calculated G and V values fall within the LMF window. The solid line forms the critical transition line for CET under directional solidification, and the dotted line indicates the threshold boundary ( G 3.4 / V = K CET with ϕ < 0.66%, Hunt's model [ 30 ] ) where CET takes place above the dotted line for the LMF process. For CMSX‐4 Ni‐base SX superalloy, K CET = 2.7 × 10 24 K 3.4 [m 4.4 s] −1 .…”

Section: Epitaxial Growth Mechanism In Am Processesmentioning

confidence: 99%

“…Modeling of epitaxial growth and SG formation helps to understand the underlying physical nature and can provide a basis for customizing solidification textures by adjusting process parameters and conditions. Various modeling techniques have been employed based on the work of Hunt [ 30 ] and Gäumann et al, [ 10 ] which focus on the prediction of microstructure evolution with epitaxial grain growth under AM scenarios. [ 51,52,120 ] Liu and DuPont [ 87,101 ] built a mathematical model for predicting 3D melt pool geometry and its effect on the crystal growth during laser melting process.…”

Section: Modeling Of Epitaxial Growth In Ammentioning

confidence: 99%

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Epitaxial Growth and Stray Grain Control toward Single‐Crystal Metallic Materials by Additive Manufacturing: A Review

Liu

Shi

2023

Adv Eng Mater

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Additive manufacturing (AM) possesses tremendous potential in controlling epitaxial growth of deposited materials, and thus attempts have been made to employ AM technology to fabricate or repair single‐crystal (SX) metal parts in recent years. One of the key issues in producing SX structures is the elimination of stray grain (SG) formation, but the layer‐wise fabrication nature of AM processes makes SGs difficult to avoid. Herein, the state‐of‐the‐art developments in this emerging research area are surveyed. It introduces the fundamental mechanisms of epitaxial growth in AM, summarizes the recent innovations and findings on using AM techniques to assist epitaxial growth and avoid SGs for SX metallic materials, discusses the relation of stray‐grain avoidance and crack‐free microstructure, and reviews the analytical and numerical modeling efforts for epitaxial growth and texture control. In addition, the challenges in achieving defect‐free SX microstructure are discussed, such that future research directions are pointed out. It is believed that this critical review provides insights on microstructure control for AM‐produced metallic materials and lays a solid foundation to stimulate more rigorous research.

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\frac{G^{n}}{V} > K_{CET}

K_{CET} = a {(\sqrt[3]{\frac{- 4 π N_{0}}{3 ln false(1 - ϕ false)}} \frac{1}{n + 1})}^{n}

in which a and n are material‐related constants.…”

Section: Epitaxial Growth Mechanism In Am Processesmentioning

confidence: 99%

Section: Epitaxial Growth Mechanism In Am Processesmentioning

confidence: 99%

Section: Modeling Of Epitaxial Growth In Ammentioning

confidence: 99%

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Epitaxial Growth and Stray Grain Control toward Single‐Crystal Metallic Materials by Additive Manufacturing: A Review

Liu

Shi

2023

Adv Eng Mater

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“…Meanwhile, Hunt [ 47 ] proposed that the condition that the equiaxed grain appeared ahead the columnar front could be expressed as Equation (7)

$$G &amp;amp;amp;amp;amp;amp;lt; 0.617 N_{0}^{\frac{1}{3}} \left[\right. 1 - \left(\left(\right.

…”

Section: Modification Mechanism Of Cerium On Solidification Structurementioning

confidence: 99%

Effects of Cerium Addition on Inclusions and Solidification Structure of a Low‐Nickel Si–Mn‐Killed Stainless Steel

Zhang

Ren

Huang

et al. 2023

steel research int.

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The effect of cerium on inclusions and solidification structure of a low‐nickel Si–Mn‐killed stainless steel is studied using laboratory experiments. When the cerium content in steel increased from 0 to 250 ppm, modification sequence of inclusions is Si–Mn(–Al)–O and MnS → Ce–Si–Mn–O–S → Ce(–Si)–O–S → CeS and CeC2. The number density and area fraction of inclusion first decrease with the increase in the cerium content and then increase due to the formation of CeC2 inclusions when the cerium content is bigger than 150 ppm, which is precipitated in solid steel during solidification. When the cerium content increases from 0 to 250 ppm, the fraction of equiaxed grain zones of steel ingot first increases and reaches a maximum value when the cerium content is 54 ppm; then the fraction of equiaxed grain zones decreases with the increase of the cerium content. 2D lattice misfit calculations are performed and it is found that there are no heterogeneous nucleation cores in the steel without cerium during solidification. For the steel with cerium, Ce4.67Si3O13, Ce2O2S, and CeS inclusions act as heterogeneous nucleation cores, increasing the fraction of the equiaxed grain zone. Bigger effective heterogeneous nucleation cores number density leads to a larger fraction of the equiaxed grain zone.

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Simplicity in protective relaying

Cited by 2 publications

References 0 publications

Epitaxial Growth and Stray Grain Control toward Single‐Crystal Metallic Materials by Additive Manufacturing: A Review

Epitaxial Growth and Stray Grain Control toward Single‐Crystal Metallic Materials by Additive Manufacturing: A Review

Effects of Cerium Addition on Inclusions and Solidification Structure of a Low‐Nickel Si–Mn‐Killed Stainless Steel

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