Determination of the Origin of Anomalous Eutectic Structures from In Situ Observation of Recalescence Behaviour

Andrew M. Mullis; Caroline R. Clopet; Robert F. Cochrane

doi:10.4028/www.scientific.net/MSF.790-791.349

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HomeMaterials Science ForumMaterials Science Forum Vols. 790-791Determination of the Origin of Anomalous Eutectic...

Determination of the Origin of Anomalous Eutectic Structures from In Situ Observation of Recalescence Behaviour

Abstract:

A melt encasement (fluxing) method has been used to undercool Ag-Cu alloy at its eutectic composition. The recalescence of the undercooled alloy has been filmed at high frame rate. At low undercooling lamellar eutectic is observed to grow, giving way to a mixed anomalous-lamellar structure at higher undercooling. In situ observation of the spot brightness reveals, as expected, that the lamellar eutectic grows via a planar front mechanism, while the anomalous eutectic grows via a more complex process characterised by a double recalescence. The first recalescence is non-space-filling (dendritic) in character and is followed shortly afterwards by a second recalescence which appears to be of the planar front type. Moreover, the first recalescence event appears to be to a temperature in excess of the equilibrium eutectic temperature. This is strongly suggestive that the anomalous eutectic morphology arises due to the growth and subsequent partial remelting of a dendritic morphology, probably a two-phase (eutectic) dendrite, followed by planar front growth of a lamellar eutectic into the residual liquid.

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Materials Science Forum (Volumes 790-791)

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349-354

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https://doi.org/10.4028/www.scientific.net/MSF.790-791.349

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Online since:

May 2014

Authors:

Andrew M. Mullis*, Caroline R. Clopet, Robert F. Cochrane

Keywords:

Eutectic Solidification, In Situ Imaging, Rapid Solidification, Undercooling

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