Composite or Carbon N1 Fan Hub

[Guptar]

If N1 fan blades can be made of composites - why can't the fan hub/fan disk also be made from composite/carbon fiber etc.
A large engine N1 disc is a hefty piece of metal of around 200 kg at a guess. Surely there is a lot of weight to be saved.

Some other items that I can think of that are still made from metals - by why can't they be carbon/composite as well
- landing gear legs
- Engine pylon struts . These items are rather heavy. If they can make a wing spar from carbon, why not these bits.

[lomapaseo]

Kind of difficult to adjust a warp and woof weave and balance against different ratios of tangential and radial stress fields.in an economical way.

They even have tried developing material properties that vary along these lines in metals, but the manufacturing costs were prohibited.

Good old titanium still fits well in aircraft technology of today in moderate temperature operations.

[Uplinker]

Don't know,; can carbon fibre withstand shock loads and vibration?

It certainly has a very high strength to weight ratio, but if hit above its strength limit doesn't it absorb the shock by disintegrating?
And does carbon fibre have any 'give'? A metal item will flex under normal use and permanently bend or creep under overload.

How robust is carbon fibre to surface abrasion? Would surface scratches weaken the structure?