Modeling Temperature in Coupled Electrical and Thermal Simulations of the Electroconsolidation® Process

Chang, F. C.; Fessler, R. R.; Merkle, B. D.; Borton, J. M.; Goldberger, W. M.

doi:10.1080/02726350490422419

Cited by 4 publications

(1 citation statement)

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“…Because of the complex nature of various phenomena involved in SPS, only a relatively moderate number of modeling attempts have been undertaken until presently 1–56 . One of the most important questions: which factors provide accelerated densification and, in many cases, limited grain growth under SPS compared with regular hot pressing applied to the same material systems, still remains unanswered.…”

Section: Introductionmentioning

confidence: 99%

Impact of Thermal Diffusion on Densification During SPS

Olevsky

Froyen

2009

Journal of the American Ceramic Society

204

103

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Spark-plasma sintering (SPS) has the potential for rapid (with heating rates reaching several hundred K/min) and efficient consolidation of a broad spectrum of powder materials. Possible mechanisms of the enhancement of consolidation in SPS versus conventional techniques of powder processing are categorized with respect to their thermal and athermal nature. This paper analyzes the influence of thermal diffusion, which is an SPS consolidation enhancement factor of a thermal nature. The Ludwig-Soret effect of thermal diffusion causes concentration gradients in two-component systems subjected to a temperature gradient. The thermal diffusion-based constitutive mechanism of sintering results from the additional driving force instigated by spatial temperature gradients, which cause vacancy diffusion. This mechanism is a commonly omitted addition to the freesurface curvature-driven diffusion considered in conventional sintering theories. The interplay of three mechanisms of material transport during SPS is considered: surface tension-and external stress-driven grain-boundary diffusion, surface tensionand external stress-driven power-law creep, and temperature gradient-driven thermal diffusion. It is shown that the effect of thermal diffusion can be significant for ceramic powder systems. Besides SPS, the results obtained are applicable to the ample range of powder consolidation techniques, which involve high local temperature gradients.The case study conducted on the alumina powder SPS demonstrates the correlation between the modeling and experimental data. It is noted that this study considers only one of many possible mechanisms of the consolidation enhancement during SPS. Further efforts on the modeling of field-assisted powder processing are necessary.

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Section: Introductionmentioning

confidence: 99%

Impact of Thermal Diffusion on Densification During SPS

Olevsky

Froyen

2009

Journal of the American Ceramic Society

204

103

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Consolidation/synthesis of materials by electric current activated/assisted sintering

Orrù

Licheri

Locci

et al. 2009

Materials Science and Engineering: R: Reports

1,137

546

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Consolidation enhancement in spark-plasma sintering: Impact of high heating rates

Olevsky¹,

Kandukuri²,

Froyen³

2007

Journal of Applied Physics

251

133

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Spark-plasma sintering (SPS) provides accelerated densification and, in many cases, limited grain growth compared to regular hot pressing and sintering. Possible mechanisms of this enhancement of the consolidation in SPS versus conventional techniques of powder processing are identified. The consolidation enhancing factors are categorized with respect to their thermal and nonthermal nature. This paper analyses the influence of a major factor of thermal nature: high heating rates. The interplay of three mechanisms of material transport during SPS is considered: surface diffusion, grain-boundary diffusion, and power-law creep. It is shown that high heating rates reduce the duration of densification-noncontributing surface diffusion, this favors powder systems’ sinterability and the densification is intensified by grain-boundary diffusion. Modeling indicates that, besides the acceleration of densification, high heating rates diminish grain growth. The impacts of high heating rates are dependent on particle sizes. Besides SPS, the obtained results are applicable to the broad spectrum of powder consolidation techniques which involve high heating rates. The conducted experiments on SPS of an aluminum alloy powder confirm the model predictions of the impact of heating rates and initial grain sizes on the shrinkage rates during the electric current-assisted consolidation. It is noted, that this study considers only one of many possible mechanisms of the consolidation enhancement during SPS, which should stimulate further efforts on the modeling of field-assisted powder processing.

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Modeling Temperature in Coupled Electrical and Thermal Simulations of the Electroconsolidation® Process

Cited by 4 publications

References 0 publications

Impact of Thermal Diffusion on Densification During SPS

Impact of Thermal Diffusion on Densification During SPS

Consolidation/synthesis of materials by electric current activated/assisted sintering

Consolidation enhancement in spark-plasma sintering: Impact of high heating rates

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