Isothermal coarsening of dendritic equiaxial grains in Al15.6wt.%Cu alloy

David R Poirier, S. Ganesan, M. Andrews, P. Ocansey

Research output: Contribution to journalArticle

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Abstract

The isothermal coarsening of equiaxial dendritic grains in Al15.6wt.%Cu alloy at 826 K (5 K above the eutectic temperature) was studied. For very short times (less than 60 s), the structure ripened by the usual increase in the secondary dendrite arm spacing. The secondary arms also coalesced and liquid inclusions formed within the grains. Simultaneously there was some fragmentation, in that the average center-to-center distance λ between grains at first decreased and then, at approximately 400 s, λ increased chth time. For times greater than 900 s, λ increased very slowly, and the morphology of the grains changed from dendritic globular to globular, when the original dendritic structure was no longer discernible. Using the surface-area-to-volume ratio Sv of the solid as the characteristic metric, a kinetic analysis showed that Ostwald ripening could not explain the results. Coalescence was identified as a mechanism, but unlike previous work, a t- 1 3 dependence of Sv on time t was not observed.

Original languageEnglish (US)
Pages (from-to)289-297
Number of pages9
JournalMaterials Science and Engineering A
Volume148
Issue number2
DOIs
StatePublished - Dec 14 1991

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Coarsening
Ostwald ripening
dendrites
Coalescence
eutectics
Eutectics
coalescing
fragmentation
spacing
inclusions
Kinetics
kinetics
Liquids
liquids
Temperature
temperature

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Isothermal coarsening of dendritic equiaxial grains in Al15.6wt.%Cu alloy. / Poirier, David R; Ganesan, S.; Andrews, M.; Ocansey, P.

In: Materials Science and Engineering A, Vol. 148, No. 2, 14.12.1991, p. 289-297.

Research output: Contribution to journalArticle

Poirier, David R ; Ganesan, S. ; Andrews, M. ; Ocansey, P. / Isothermal coarsening of dendritic equiaxial grains in Al15.6wt.%Cu alloy. In: Materials Science and Engineering A. 1991 ; Vol. 148, No. 2. pp. 289-297.
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