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Non-Equilibrium Solidification of Undercooled Metallic Melts

Herlach, Dieter M. (2014) Non-Equilibrium Solidification of Undercooled Metallic Melts. Metals (4), pp. 196-234. Multidisciplinary Digital Publishing Institute (MDPI). doi: 10.3390/met4020196. ISSN 2075-4701.

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Official URL: http://www.mdpi.com/jurnals/metals

Abstract

An undercooled melt possesses an enhanced free enthalpy that enables to crystallize metastable solids in competition with their stable counterparts. Crystal nucleation selects the crystallographic phase whereas the growth dynamics controls microstructure evolution. We apply containerless processing such as electromagnetic and electrostatic levitation to containerlesss undercool and solidify metallic melts. Heterogeneous nucleation on container-walls is completely avoided leading to large undercooling with the extra benefit that the freely suspended drop is direct accessible for in situ observation of crystallization far away from equilibrium. Results of investigations of maximum undercoolability on pure zirconium are presented showing the limit of maximum undercoolability set by the onset of homogeneous nucleation. Rapid dendrite growth is measured as a function of undercooling by a high-speed camera and analysed within extended theories of non-equilibrium solidification. In such both supersaturated solid solutions and disordered superlattice structure of intermetallics are formed at high growth velocities. A sharp interface theory of dendrite growth is capable to describe the non-equilibrium solidification phenomena during rapid crystallization of deeply undercooled melts.

Item URL in elib:https://elib.dlr.de/92394/
Document Type:Article
Title:Non-Equilibrium Solidification of Undercooled Metallic Melts
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Herlach, Dieter M.Institut für Materialphysik im WeltraumUNSPECIFIED
Date:20 June 2014
Journal or Publication Title:Metals
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
DOI :10.3390/met4020196
Page Range:pp. 196-234
Publisher:Multidisciplinary Digital Publishing Institute (MDPI)
ISSN:2075-4701
Status:Published
Keywords:Undercooling, non-Equilibrium solidification, containerless processing, nucleation, growth kinetics, sharp interface theory
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Research under Space Conditions
DLR - Research area:Raumfahrt
DLR - Program:R FR - Research under Space Conditions
DLR - Research theme (Project):R - Vorhaben Materialwissenschaftliche Forschung (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Physics in Space > Scientific Experiments MP
Deposited By: Klein, Stefan
Deposited On:25 Nov 2014 08:48
Last Modified:14 Dec 2019 04:22

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