by George Langford, Sc.D., Massachusetts Institute of Technology, Cambridge, MA, 1966
2005 by George Langford
This is the fourth lesson in a set of images that I made that demonstrate metallurgical microstructures in the specimens in the M.I.T. collection.  This is the last of the non-ferrous specimens.  This lesson is entirely about aluminum alloys.  Since aluminum generally holds less solute than iron orcopper, there are a lot of extraneous inclusions and other more or less desirable phases.  The KA-135 color transparency film had a color temperature problem, so I have had to adjust the color balance of all the images.  The aluminum itself looks off-white to light grey through the microscope, and the silicon looks a dark grey to blue grey.  Other colors are artifacts in these images.
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.
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.