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Containerless Processing in the Study of Metastable Solids from Undercooled Melts

Herlach, D.M. (2013) Containerless Processing in the Study of Metastable Solids from Undercooled Melts. In: Applied Mechanics and Materials, 526, pp. 21-27. Trans Tech Publications, Switzerland. 2013 International conference on Materials Engineeering for Advanced Technologies (ICMEAT 2013), 31. Dez. 2013 - 02. Jan. 2014, Brisbane, Australien.

Full text not available from this repository.

Official URL: http://www.scientific.net/AMM.526.21

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/87936/
Document Type:Conference or Workshop Item (Speech)
Title:Containerless Processing in the Study of Metastable Solids from Undercooled Melts
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Herlach, D.M.dieter.herlach (at) dlr.deUNSPECIFIED
Date:December 2013
Journal or Publication Title:Applied Mechanics and Materials
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Volume:526
Page Range:pp. 21-27
Publisher:Trans Tech Publications, Switzerland
Status:Published
Keywords:Containerless processing; Undercooling; Crystal nucleation; Dendritic growth; Supersaturated alloys; Disorder trapping; Metastable solids.
Event Title:2013 International conference on Materials Engineeering for Advanced Technologies (ICMEAT 2013)
Event Location:Brisbane, Australien
Event Type:international Conference
Event Dates:31. Dez. 2013 - 02. Jan. 2014
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 - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):R - Vorhaben Materialforschung unter Mikro-g (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Physics in Space > Scientific Experiments MP
Deposited By: Gegner, Jan
Deposited On:29 Jan 2014 08:25
Last Modified:08 May 2014 23:31

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