[mk_stjames]

When you hear 'Titanium' mentioned in an engineering sense, rarely is this a reference to elemental titanium alone; structures use alloys of titanium which means small percentages of other metals are added (aluminum and vanadium for example are the two principle alloying metals in Grade 5 titanium, 6AL4V, probably the most common in aerosapce applications), and then the wrought products are even further processed through solution heat treating, etc. The same goes for aluminum, steels, etc. This is the purpose of the entire field of metallurgy....

Your comment would be like the equivalent in computer science of saying "Why do you need to write a computer program; the computer either works or it doesn't..."

[Animats]

Titanium is metallurgy on hard mode.[1] Iron and steel behave in a much more consistent way.

[1] https://www.sciencedirect.com/science/article/abs/pii/S09215...

[dr_orpheus]

And even after you get past the manufacturing, titanium also seems to have some weird corner cases. I learned recently about metal induced embrittlement of titanium [0]. The Wikipedia article mentioned cadmium embrittlement of titanium, but is also possible with copper and silver. So if you have a silver plated washer pressed in to titanium it can cause issues.

[0] https://en.wikipedia.org/wiki/Metal-induced_embrittlement

[justin66]

If I remember correctly, in Ben Rich's book he mentioned that LA's water in the summertime was chlorinated enough that the titanium welds on the early A-12 would sometimes fail because of a chemical reaction they didn't anticipate - they were embrittled because they were flushed with that water, I think?

[hinkley]

This year I learned titanium shavings are at least as dangerous as magnesium shavings.

[mrspuratic]

recent: https://news.ycombinator.com/item?id=38394635 The story of titanium

[MBCook]

So a bit like a sheet of carbon vs carbon fiber?

The carbon is an important part of the final material but it’s not really comparable.

[zardo]

In addition to the actual alloy the paperwork could cover x-ray inspection for defects.