Hi Won, all well here, hope you are still enjoying working on puddle jumper car
WRC is an itch I need to scratch one day so I'm only jealous
Interesting fan blade, learnt a lot watching the first video thanks
Titanium and carbon go together very well and is one of the more common combinations of metallic/composite materials used together in F1 composite parts. The expansion rates of carbon and titanium are a good match and it is possible to easily bond the two materials together.
An F1 carbon floor will sometimes have the outboard front corners protected with a bonded on thin titanium machined capping piece to stop the floor wearing away to dust from the grit and dirt thrown up by the front wheel. As seen below
This is exactly the same concept behind the way the fan blade has been designed and manufactured.
I've used titanium with very good results laminated into all sorts of more complicated composite structures. A gearbox casing is a good example as the titanium can be precision machined so bearings can be pressed in or where a threaded fixing holes is required. Best picture I can find showing this is a gearbox maincase from an Audi Le Mans car, they even went further and used ti for the suspension mounting lugs.
Carbon is a great material to use but as with all materials it has its limitations
Probably the number one rule I try and work to when designing composite parts is to keep the carbon simple and put the complexity into the metal. Reason being the carbon plies are hand applied so are have a wider manufacturing tolerance and a finer level of detail can be machined into any metallic inserts or bonded on metallic parts without compromising the stiffness/strength.