Full Record for Micrograph 617

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Micrograph no: 617
Brief description: Deeply etched Co-dendrites
Keywords: alloy , cobalt, copper, deep-etched, dendrite , 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-Non-Commercial-Share Alike 2.0 UK: England & Wales