Below is another photomicrograph of the same specimen, shown at 500X.
What treatment has it had ?
Pause to think about your answer before peeking.
|
The photomicrograph at left, shown at 100X, is of a
manganese bronze composed of copper, 39% zinc, 1.5% iron, 1% tin, and
0.1% manganese. Below is another photomicrograph of the same specimen, shown at 500X. |
|
The blue "stars" are an iron-zinc compound; they are a
distinguishing characteristic of this alloy. What treatment has it had ? Pause to think about your answer before peeking. |
| It's been cast. The colors
were not quite true in the original slides, so I adjusted the color
balance of each image. In the original specimen the beta matrix
was yellow, with pink islands of alpha; the digitally enhanced images
approximate these colors fairly well, but the "stars" now have an
exaggerated blue color. The few shrinkage pores and
the absence of annealing twins pin down the "as cast" conclusion. |
| The third specimen is a naval brass with a solvable brittleness problem. |