Just for a little reading information, i found this site describing knife materials. Seems to me that our broadheads should or are made out of knife blade materials. Very interesting stuff. The lists usually start with the cheap stuff and progress to the "good" stuff.
So next time a broadhead manufacturer says they use "bla bla" steel and it is the best, you will have been better informed about what they are talking about.
http://cutleryscience.com/reviews/blade_materials.html#T_10V
Rob