This is a really thorough series of atricles on the properties of bicycle framing materials.
I wasn't sure if it belonged here, but decided the only other place would be "open." And I thought it deserved to be classified somewhere. I am not sure how long this link will last, as the home page it comes from has been declared out-dated.

http://www.sjsu.edu/orgs/asmtms/artcle/articl.htm

Mary