What about work hardening of metals as they become brittle with age and stress imposed on them. Bend a piece of metal enough and it becomes brittle and will fracture easily. Do composites react in the same way and/or have a more "elastic" property giving rise to longer life?
How after an accident on a composite aircraft do you try to find the cause if its structural and not the obvious.If its metal you can detect age hardening of the metal by detailed analysis,( Comet disaster) This physical property I would suspect, may not be present in composites...i dont know??, so when faced with millions of pieces of composite you dont know which let go due to stress and which are a result of the impact during the accident ...do composites show signs of aging etc etc that can be scrutinised in the event of failure?? if the composites have melted away in the ensuing fireball would this leave forensic analysis more difficult..i'd suspect so. I only did metalurgy to OND level as a small module of a general engineering qualification ..and composites werent in abundance then.