| Unknowns |
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INTRODUCTION
The first set of unknowns is based on
photomicrographs I made of eight specimens that are in the M.I.T.
collection.
In order to build up your confidence and test your ability to interpret
microstructures, only minimal help and hints are given in this
section. At the end of the description of each unknown specimen,
there will be a link to the answer. However, the answers are
individually password protected; you can email me at the address imaged
above
to get a Username and Password to access those answers.
Naturally, I'll expect some small proof that you have made an effort to
work out some answers, in the form of an included written outline of
your
analysis. There is no charge for
this. These unknowns and others like them were doled out one at a
time at M.I.T., one each week to each student, so you should not expect
that your analysis will just leap out at you from the computer
screen. It takes time (or experience) for that to happen.
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I made the color
photomicrographs presented here of a prepared set of
specimens of known history collected by the staff of M.I.T. in the
years prior to 1959. They were made by me with Kodachrome KA135
Professional, but the color temperature of the illumination was still
way too low for proper rendition of the color of the light reflected
from the specimens. I have therefore adjusted the color balance
to approximate better what I remember seeing through the eyepieces of
the microscope. The microscope objective lenses used were
achromatic
(corrected for two colors) and, as the appropriate green filter was not
used, there are sometimes color fringes and reduced resolution as a
result of the use of the panchromatic color film.
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Allow plenty of
time to study and to take good notes about each specimen. About
two hours per lesson would be appropriate. You will be expected
to interpret some of these specimens during the final
examination. Feel free to use the Internet to find additional
information about the alloys and applications mentioned here.
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Whenever the
narrator asks a question, be sure to commit yourself to an answer
before going to the next page. You can backtrack with your
browser's BACK button at any time, of course. Just be sure to click
the FORWARD button to return to the proper page before proceeding so
that you don't get
lost.
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Unknowns -
First Set - Iron-Based
Second
Set - Non Ferrous (do this
second -- it's harder)
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