FAA Flags Unapproved Titanium in Boeing 787 Ram Air Turbines

Eric Rindal is of course right, that un-approved is not necessarily inferior.
However, in this case, the post gives us more information, specifically:
"the suspect material is either Grade 1 or Grade 2 commercially pure titanium, which offers significantly less strength, fatigue resistance, and damage tolerance than the Grade 5 Ti-6Al-4V alloy originally specified".
"Commercially pure titanium" is at least 99% pure Titanium.
"Grade 5 Ti-6Al-4V" is about 94% Titanium, 6% Aluminum, and 4% Vanadium.
(You see the alloy composition in the name.)
These are two very different metals.
For a reliable, readable summary of the relevant metallurgy, start here :
https://titanium-gateway.com/vanliga-fragor/what-is-pure-titanium
For completeness I note that this is a website of a Swedish Company; I find it to be accurate.
[I have two artificial shoulders. The implants are stainless steel coated with a plasma spray of "commercially pure titanium". It has excellent corrosion resistance, and is biologically essentially inert, but it is not high strength, and not suitable for use in an aerospace structure.]

UN-approved is not necessarily inferior. just not specifically from a previously approved supply chain source. As stated, "potentially" inferior due to a lack of certification tests. Again as stated. test the blades. If conforming, certify the source.

Well, at least it's only 9 airframes.

Any source of inferior materials of any sort is a concern in any industry or field. Many years ago, the Chinese were accused of dumping boat loads of inferior steel brake rotors into the US market at rock bottom prices undercutting other sources of such, and were fined for dumping said brake rotors in said markets.

It would not surprise me that they were selling inferior titanium to aircraft parts manufacturers.

(Spellcheck). Sigh…

Why highlight the 787, when this anpplies to other aircraft as well, including the A220?

The good news is that the RAT is one of the least-likely-to-be-used components on the 787. It only deploys in a drastic situation such as a dual engine failure or multiple hydraulic or electric generator failures.

Of course, we all saw this happen in the Air India crash, but being close to the ground without both engines, the RAT didn't offer much help.

Certainly, as a component of last resort, we'd like it to work. And any fraud in the supply chain is definitely a concern (I've had such issues with the ignition system on my plane). However, I think that this is one that you can fix at next-scheduled-maintenance.

A good part of this discussion is totally uninformed beliefs. Not very useful. As a scientist, I check and recheck my data sources before I speak. Political statements and inuendo are not very useful in an engineering environment. Shut up.

The Chinese will always cut corners when they can. It is rampant throughout their culture.

Which airlines, and which aircraft would be helpful to know.

The use of such materials came amid global titanium shortages caused by Western sanctions against Russia -
Another case of ''bite off your nose to spite your face''