Aluminum Bronze

Casting |

I've been toying with making small quantities of bronze just for fun. Tin in raw form has been challenging to find, although I think I tracked down a supplier for small quantities. I have had no luck whatsoever finding elemental silicon in sufficient quantity at a reasonable cost. I did read some interesting articles on properties of aluminum bronze, and have tried a couple of tests there, (see below) and have a good supply of clean/pure copper in cable form that's easy to chop up to size for the (A6 graphite/clay) crucible I'm using. The furnace is propane fired.

When I made the aluminum bronze (minus the silicon and/or manganese, as I don't have any) I melted the copper first, then added aluminum (8% one time, 10% the next by weight). Once the aluminum melted, a strange thing happened: When I gave everything a good stir, the melt IMMEDIATELY became much brighter, almost white from orange/yellow as if the temperature had jumped significantly (although there was no noticable viscosity change). Can anyone comment on what happens here? Incidentally, the mix makes a very pretty alloy = )

-Roy


B.J. Severtson's picture

What happened

Roy,
This is what I believe happened. You observed the eutectic principle happen. Aluminum may be an all the rules breaker. It's been along time since I played with those alloys. The mixture of both melted metals fused to form an alloy, the alloy has a melting point between the temps of it's components..color change is one of the reasons metals are alloyed. For fun check out a purple gold alloy aluminum and gold..Wow color but not a workable material as I remember. People that do mokome will frequently do some of their own alloying check them out. There was a good article on alloying in lapidary journal a few years back. Worth looking for. Fun in the metals shop. Brad