As far as I can tell, it's only the fretboard and the frets that are aluminum.
The rest of the neck is, as you say, some other material.

If anyone else has one with a warped neck, you may be able to straighted it
by just removing the strings and carefully putting it into a vice.
Then add heat (even just boiling water) TO THE FRETBOARD ONLY.
Then twist it straight and hold it until it cools.

Just a thought. I've never had to try it.
LLOYD S