Alloy: : a substance composed of two or more metals or of a metal and a nonmetal intimately united usually by being fused together and dissolving in each other when molten
Them there things are called "wheels".
Take a picture of the wheel from dead on.
Do a google image search.
Call the manufacturer if you get a hit or close to a hit and ask if it's their wheel design.
You may have better luck with finding a manufacturer code or name on the back of the wheel though, as suggested.