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Aluminum Copper Alloy Experiment

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SwarfnStuff:
Hi Norman,
     My first thought was Aluminium Bronze (as did Mathew ) so off to Wikipedia and it does seem you have the basis for it.
  Whatever it really is perhaps only a metallurgist could tell but hey, if it does what you  want I'd say that's a win.
   As for the work-hardening, well you have 90% copper which we all know does just that It might be interesting to try a different ratio (75:25 perhaps) and see how that performs.
 One century I might just get my furnace finished and fired up but life seems to be interrupting things.
John B

NormanV:
I've machined a piece of it, it is hard. HSS won't touch it, I had to use a carbide tool. It gives a good finish.




I want to try annealing it to see if I can make it easier to machine. I don't understand annealing, it seems that I have to heat it up and then allow it to cool. Isn't that was just happened when I poured it into the mould?
Could someone advise me on annealing please?
Thanks.

AdeV:
Annealing varies by metal. Plain copper; yeah, heat it to cherry red, hold it for a few moments, then let it cool (the slower the better). Similar for steel. For ali-bronze? I have no idea; does Machinery's Handbook cover it? [I don't have my copy to hand]

Joules:
Here you go for starters.  My own experience is to heat it up hot, with long cool down, the workshop furnace here is programable so I can set it to cool over many hours, but a hot sand bath to bury it in would also work if possible.

http://admin.copperalliance.eu/docs/librariesprovider5/pub-222---guide-to-nickel-aluminium-bronze-for-engineers/pub-222-07-heat-treatment.pdf?sfvrsn=2


Another interesting link, especially for other copper alloys.

https://www.copper.org/resources/properties/microstructure/al_bronzes.html

NormanV:
Both suggestions suggest how to anneal, thank you. I have done that and am waiting for it to cool down. My real question is why is the metal not soft after it cools down after casting?
Another question. I have watched a number of videos of metal being forged, as it is done large amounts of slag, I think that is what you call it, falls off. I have just been trying to clean my mild steel crucible after casting the bronze. As I did it a lot of slag fell off the outside of the crucible, what exactly is this slag? It measured 0.8mm thick, quite substantial, but the crucible still has its integrity.

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