What part on a Bf109 or FW190 matches this?
I recall seeing stories about recovering WWII aircraft wreck in England where the engine could bury itself 20' deep if the plane crashed in the right kind of soil, angle and speed
It's sort of a 2000 series Al alloy. Like 2219, but the Mn and Si don't match anything else. That's why my vote is for something German from late WWII, and the slave labor at the foundry was just blending the melt to be "close", With lots impure scrap and wrong blends. Late war, desperate, hurried production.
They should do some metallography on it too.
Just to make sure it wasn't manufactured in the gravity well in a binary star system. I recall some UFO authority saying that's how the Roswell aliens made the superalloys used on their crashed vehicle.
Now I still think at the last place I worked, that the AF brought in some of the first samples of a Ti alloy and said, "here, make us more of this. We can't tell you where it came from, or how it was made". Because there sure weren't anyone there in R&D smart enough to figure out how to process it, much less invent an alloy that was useful. I want to believe some of those samples came from crashed objects or unknown origin.