You can grow a turbine blade out of one crystal of titanium rather than many which improves the strength.

Here's an amazing video about other parts of the structure and construction of Rolls Royce titanium turbine blades. It's awesome.

I've no idea about inconel...

https://www.youtube.com/watch?v=aFRdp1Js9Kc

You're mistaken about all solid metal being crystalline - look up amorphous metal. I've held a ribbon of it, it's quite impressive how it flexes. https://en.m.wikipedia.org/wiki/Amorphous_metal

> And all solid metal is crystalline.

https://en.wikipedia.org/wiki/Amorphous_metal

See https://en.wikipedia.org/wiki/Superalloy

SpaceX "3D Prints" their merlin engine chambers from the same alloy, inconel.

http://www.spacex.com/news/2014/07/31/spacex-launches-3d-pri...

SpaceX's entire Super Draco rocket engine is 3d printed, too.

Some axial turbines have ceramic blades