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Deeply etched dendrites (cobalt samarium copper)

DoITPoMS, University of Cambridge

 

Using this alloy composition, a relatively low volume fraction of pro-eutectic dendrites is formed. Due to their different chemistry the eutectic interdendritic Sm and Cu enriched phases material between these dendrites can be etched away to reveal the three-dimensional structure of dendrites. The dendrite tips are a volume have the form of a paraboloid of revolution, 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.

 

System

Co-Sm-Cu

 

Composition

Co 70, Sm 10, Cu 20 (at%)

 

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 eutectic material Sm and Cu enriched phases between the primary dendrites.

 

Technique

Scanning electron microscopy (SEM)

 

Contributor

Prof W Kurz

 

Organisation

Department of Materials, Swiss Federal Institute of technology (EPFL), Lausanne, Switzerland

 

View micrograph in DoITPoMS website

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Uploaded on August 20, 2009
Taken on October 3, 2002