Dissemination of IT for the Promotion of Materials Science (DoITPoMS)

DoITPoMS Micrograph Library Full Record for Micrograph 617

Full Record for Micrograph 617

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Micrograph no
617
Brief description
Deeply etched Co-dendrites
Keywords
alloy Link to MATTER Glossary entry for alloy, cobalt, copper, deep-etched, dendrite Link to MATTER Glossary entry for dendrite, etching Link to MATTER Glossary entry for etching, metal, samarium
Categories
Metal or alloy
System
Co-Sm-Cu
Composition
Co 70, Sm 10, Cu 20 (at%)
Standard codes
Reaction
Processing
Directionally solidified in a Bridgman apparatus
Applications
Sample preparation
After directional solidification the cobalt-samarium-copper alloy has been deeply etched with 10% nitric acid in ethyl alcohol (10%Nital) to remove the Sm and Cu enriched phases between the primary dendrites.
Technique
Scanning electron microscopy (SEM)
Length bar
80 μm
Further information
Using this alloy composition, a relatively low volume fraction of dendrites is formed. Due to their different chemistry the interdendritic Sm and Cu enriched phases can be etched away to reveal the three-dimensional structure of dendrites. The dendrite tips have the form of a paraboloid, and anisotropy develops behind them with the secondary dendrite arms.

See R. Glardon, W. Kurz, "Solidification path and phase diagram of directionally solidified Co-Sm-Cu alloys", J. Cryst. Growth, 51 (1981) 283-291.
Contributor
Prof W Kurz
Organisation
Department of Materials, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
Date
03/10/02
Licence for re-use
Attribution-NonCommercial-ShareAlike 4.0 International