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Comment by redcalx | Hacker News Reader

I assume they're titanium. I wonder though if they use titanium crystals as per jet engine turbine blades?

"A routine check of the aluminum wheels" - first sentence of the article.

Titanium is heavier than Aluminium and only a little bit stiffer, so it's not necessarily a good choice for a weight-sensitive load bearing part even with unlimited budget.

However, the pure/single crystalline form is potentially strong enough that it would be possible to use less material than for the non-crystalline form.

The wheels are all ready only like .65 mm thick, how much thinner do you want them to be?

If using mono-crystalline titanium can achieve the same hardness, strength, durability, etc. at less mass then why wouldn't you choose that option?

The tread is 0.65mm thick.

Turbine blades are made from inconel. And all solid metal is crystalline.

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

The article states they're milled out of solid aluminum

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