Density, modulus, and Fatigue - Oh my

I've been a bit overwhelmed as of late researching bike geometries, qualities, materials, and what have you. I'm always curious as to what other people think, and even more curious as to why they think what they do. Folklore is a mighty powerful beast, often overpowering even the mightiest of bike gurus. The strongest of them always come down to a few: aluminum is a harsh ride, steal is heavy, and carbon fiber doesn't last more than 5 years. I'll admit I've sort of bought into these tales to some degree over the years, but probably not to the degree that say most consumers think all Trek bikes are good because they are Treks. Well actually no, most of them are junk in fact.

So I've taken it upon myself to do some more research mostly for a friend, but also for the day that I can actually afford a nice light road bike that fits me snugly, or that sick Titanium XC mountain racer. For now I've stumbled upon a series of articles called METALLURGY FOR CYCLIST by Scot Nicol who founded Ibis Cycles.