Primary spacing selection in directionally solidified alloys

Han, Seung Hoon; Trivedi, R.

doi:10.1016/0956-7151(94)90045-0

Cited by 128 publications

(101 citation statements)

References 28 publications

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“…[6] In contrast to the previous results, significantly broad spectrum of primary spacings is presexperimental studies in bulk metallic and organic systems ent. [6] This disorder in spacings can occur due to two factors: have clearly shown the presence of a wide range of spacings a weak spacing-selection criterion, which causes a range of or a highly disordered spatial arrangement of cells and denspacings to be present, and the effect of convection in large drites. Convection effects have been assumed to be responsior bulk samples.…”

Section: Introductioncontrasting

confidence: 48%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Although the average spacing is most often was created when the spacing exceeded about 1.5 times the reported in the literature, experimental studies show that a minimum stable spacing. [6] In contrast to the previous results, significantly broad spectrum of primary spacings is presexperimental studies in bulk metallic and organic systems ent. [6] This disorder in spacings can occur due to two factors: have clearly shown the presence of a wide range of spacings a weak spacing-selection criterion, which causes a range of or a highly disordered spatial arrangement of cells and denspacings to be present, and the effect of convection in large drites.…”

Section: Introductionmentioning

confidence: 99%

“…[6] Through studies of the dynamics of tal studies have, thus, been carried out to relate primary spacing adjustments, it was shown that cells can translate spacing to the growth rate, temperature gradient, and compolaterally to minimize the disorder, and a new cell or dendrite sition. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Although the average spacing is most often was created when the spacing exceeded about 1.5 times the reported in the literature, experimental studies show that a minimum stable spacing. [6] In contrast to the previous results, significantly broad spectrum of primary spacings is presexperimental studies in bulk metallic and organic systems ent.…”

Section: Introductionmentioning

confidence: 99%

“…dendrite transition region. [6,[9][10][11][12][13][14][15][16] The primary-spacing distribution was found to be more…”

Section: Introductionmentioning

confidence: 99%

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The effect of convection on disorder in primary cellular and dendritic arrays

Trivedi

Mazumder

Tewari

2002

Metall Mater Trans A

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Section: Introductioncontrasting

confidence: 48%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…dendrite transition region. [6,[9][10][11][12][13][14][15][16] The primary-spacing distribution was found to be more…”

Section: Introductionmentioning

confidence: 99%

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The effect of convection on disorder in primary cellular and dendritic arrays

Trivedi

Mazumder

Tewari

2002

Metall Mater Trans A

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“…Similar data for other alloys are lacking in the literature from where we can extract this ratio for steady-state growth of cellular arrays. Han and Trivedi [17] have reported the Gaussian fit to the data. They observed the ratio of the maximum cell spacing to the minimum cell spacing to be 1.36, which is in reasonable agreement with 1.4 observed nature and intensity of convection present during growth of the Al-Cu and Pb-Sb alloys almost all the observations by us.…”

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confidence: 99%

Cellular array morphology during directional solidification

Tewari

Weng

Ding

et al. 2002

Metall Mater Trans A

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Cellular array morphology has been examined in the shallow cell, deep cell, and cell-to-dendrite transition regime in Pb-2.2 wt pct Sb and Al-4.1 wt pct Cu alloy single-crystal samples that were directionally solidified along [100]. Statistical analysis of the cellular spacing distribution on transverse sections has been carried out using minimum spanning tree (MST), Voronoi polygons, radial distribution factor, and fast Fourier transform (FFT) techniques. The frequency distribution of the number of nearest neighbors and the MST parameters suggest that the arrangement of cells may be visualized as a hexagonal tessellation with superimposed 50 pct random noise. However, the power spectrum of the Fourier transform of the cell centers shows a diffused single-ring pattern that does not agree with the power spectrum from the hexagonal tessellation having a 50 pct superimposed random (uniformly distributed or Gaussian) noise. The radial distribution factor obtained from the cells is similar to that of liquids. An overall steady-state distribution in terms of the mean primary spacing is achieved after directional solidification of about three mushy-zone lengths. However, the process of nearest-neighbor interaction continues throughout directional solidification, as indicated by about 14 pct of the cells undergoing submerging in the shallow cell regime or by an increasing first and second nearest-neighbor ordering along the growth direction for the cells at the cell-to-dendrite transition. The nature of cell distribution in the Al-Cu alloy appears to be the same as that in the PbSb. The ratio between the upper and lower limits of the primary spacing, as defined by the largest and the smallest 10 pct of the population, respectively, is constant: 1.43 Ϯ 0.11. It does not depend upon the solidification processing conditions.

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On the Effect of Cooling Parameters on Solidification Structure in NdFeB Alloys

Wolz,

Caniou,

Tosoni

et al. 2024

Adv Eng Mater

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The elaboration of suitable NdFeB‐based permanent magnets is essential for high‐performance electrical machines in a number of applications. In this respect, the understanding of the relationship between heat transfer phenomena and the final solidified microstructure is the key to the control of the grain size and the improvement of the magnetic properties. The problem is even more acute with the emergence of new manufacturing processes, such as the laser powder bed fusion, where the cooling rates are much higher than those encountered in the standard strip casting process and where the microstructure can be considered as fixed from the fabrication step. The objective of the present work is to identify correlations between interstructural spacings in the solidified alloys and cooling conditions. This study is based on a methodology coupling experimental and numerical simulation approaches featuring three solidification processes: strip casting, arc melting, and laser fusion. The obtained results cover more than four orders of magnitude in terms of cooling rates R and allow to propose a reliable empirical relationship between the interstructural spacing λ and R of the form λ [μm] = 83 R [K s−1]−0.36. This relation can thus be used to estimate cooling rates from metallographic observations.

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Primary spacing selection in directionally solidified alloys

Cited by 128 publications

References 28 publications

The effect of convection on disorder in primary cellular and dendritic arrays

The effect of convection on disorder in primary cellular and dendritic arrays

Cellular array morphology during directional solidification

On the Effect of Cooling Parameters on Solidification Structure in NdFeB Alloys

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