Grain refinement in highly undercooled solidification of Ni85Cu15 alloy melt: Direct evidence for recrystallization mechanism

Received 30 November 2009; received in revised form 19 January 2010; accepted 2 March 2010. published online 08 March 2010.

The grain refinement occurring upon rapid solidification of undercooled Ni85Cu15 alloy melts has been studied. Applying theoretical calculations for stress accumulation in dendritic skeletons, the grain refinement occurring with ΔT >∼180K is ascribed to plastic deformation of dendrites and subsequent recrystallization. This has been evidenced directly using high-resolution transmission electron microscopy observation of the as-solidified granular crystals.

Keywords: Undercooling, Grain refinement, Rapid solidification, Recalescence, HRTEM

State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an Shaanxi 710072, China

Corresponding author. Tel.: +86 29 88460374; fax: +86 29 88491000.

PII: S1359-6462(10)00144-2

doi:10.1016/j.scriptamat.2010.03.006

Published by Elsevier Inc.

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