Photomicrograph Database

Artifact ID BCES 1402/1320
Negative Number NS290
Magnification 100x
Etchant AH/HP, K2Cr2O7
Photo Date 7/2/2001

Alloy

bronze.

Structure

As-cast.

Metallographic Description

An amorphous specimen of unusual structure. One half has rather corroded cored dendrites with numerous voids and nonmetallic inclusions. Large amounts of alpha+delta eutectoid, both corroded and uncorroded, can be seen in this portion. There are numerous voids in this area that are filled with redeposited copper. The other portion contains large globular grains with clear grain boundaries and twins, but no eutectoid or redeposited copper. This second area is quite coppery in color. The line of demarcation, which can be seen with the naked eye, appears to be the result of alloys of distinctly different composition having impinged in the liquid state and adhered to each other. It is not clear which portion of the sample was analyzed compositionally; it may be an average.


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