It might be copper (98%) - nickel - beryllium, "CS-95® -Ultra-High Strength Copper Alloy". It can be annealed and tempered (!), welded, silver soldered, and hammered (!). Drilling, lathe work and milling is a pain of ass, but can be done. It's fairly cheap, actually.
Or it might be completely different
![:doh:](https://madmodder.net/Smileys/default/doh-45.gif)