I can only guess on MMX.... several bicycle frame companies and military jet builders market a "metal matrix" secret alloy. Some MMX include Scandium. Some Beryllium. There is quite a bit of info on the web.
If you have a metal alloy handbook, look at aluminum alloy 5056. It is non-magnetic, and does not allow even trace ferric materials. It is significangly stronger than pure Al. It has 2x the resistance of pure Al, which can make it more amplifier friendly in some designs. I can purchase small sheets of 5056 foil, but I could not find a low cost source of rolls of the material, and have developed a better construction technique.
can you inform me please where can I buy small quantity of AL alloy 5056 for my 60" full range ribbons . I tied at Aluminium Coil: Hollinbrow Precision Products (UK) Ltd
but they do not sell less than 100 kilo`s.
Thank you in advance for any kind of reply