Isaiahc72, Frames of every material have failed for one reason or another. Generally when crashed, but also if used outside of the design parameters. Warranties are just good business practice. How the manufacturer handles the claim can vary so experiences differ.

Aluminum picked up a fragile reputation in the late '80s-early '90s. Internet clatter at the time was pointed primarily towards some of the early 7XXX frames being brittle. This has long since been corrected for the 7XXX bikes. Trek's Alpha aluminum frames that were introduced in the late '90s are pretty darn good. When I researched my then new Trek 7000ZX's frame material the different resources at the time stated that it was 6013 T6 aluminum. I have beat that Trek to death on technical single track and even used it for some light touring and there is no reason to not expect it to continue for another 15 years... I will break before it will.

Brad