Author Topic: Aluminum Copper Alloy Experiment  (Read 14804 times)

Offline vtsteam

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Aluminum Copper Alloy Experiment
« on: May 18, 2015, 02:16:12 PM »
Since David (Meldonmech) in his QCTP build thread and Andrew mentioned alloying copper with aluminum to increaase hardness, I did a few lookups online (and in a book I have) and found an alloy that looked interesting using 6% silicon and 4% copper, so decided to try it with scrap onhand.

I used a 14 oz piston for silicon content (likely about 12%) and 14 oz 6061 extrusions, which would bring the silicon level to about the 6% needed, and 1.2 oz of copper tubing for the 4% copper. I flattened it and rolled it together to reduce oxidation. Here are the ingredients:



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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #1 on: May 18, 2015, 02:25:31 PM »
I wasn't sure if the aluminum would dissolve the copper directly, or whether the copper should be molten first, so I tried melting the copper to start with. After about 25 minutes and the copper glowing bright orange, it still wasn't molten, and being impatient, I started dropping some of the aluminum in. When a good heel was going I added more and eventually the piston, and had a brimfull crucible as a result.

The copper did dissolve in the aluminum, so I probaby could have saved much time and fuel had I just put them all together to begin with.
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Offline Sea.dog

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Re: Aluminum Copper Alloy Experiment
« Reply #2 on: May 18, 2015, 02:43:38 PM »
I'm new to this forum and this will be my first post.
Re the comment you make about aluminium and copper reminded me of a demonstration of eutectic alloying that our metalwork master showed the class back in the 60s.
He heated a strip of copper to a dull red then applied a thin piece of aluminium wire to the surface.It melted onto it and he then proceed to poke a hole through the strip thereby demonstrating how alloying changes the melting point.

I've enjoyed catching up on a lot of the posts since Doubleboost recommended the site and am learning a great deal. I'm keen to make a small furnace myself as the last casting that I did was 50 years ago!

Graham

Offline RobWilson

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Re: Aluminum Copper Alloy Experiment
« Reply #3 on: May 18, 2015, 02:48:34 PM »
Interesting Steve  :thumbup:  how dose your new alloy machine ? 


Rob

Offline chipenter

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Re: Aluminum Copper Alloy Experiment
« Reply #4 on: May 18, 2015, 03:06:45 PM »
I found out about the copper by mistake droped a piece of copper pipe in the furness , by the time I bent a pice of wire the fish it out half it had melted , so I added all my offcutts the resulting poure turned very nicely on the lathe into pullys .
Jeff

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #5 on: May 18, 2015, 03:11:35 PM »
I just poured ingots -- long ones so I wouldn't mix it up with my other stock in muffins.



Hi Seadog, welcome aboard! :beer: Yes it sure did dissolve easily after all.

Rob, I haven't tried machining it yet, but will. I did snap one of the thinner ingots in half in the vise with a big hammer. It definitely breaks rather than bends. It feels hard, and rings hard. But it isn't any harder than a piece of 6061 I tried scratching it on. Also, no harder than a cast aluminum part on my Gingery lathe (pure melted pistons). Not s hard as zamak za-2. But it did scratch some of my newer stock of ingots (also pistons). Not much harder than them, though. I'm guessing the difference may be due to aging of the castings and 6061, possibly making them harder, while the newer ingots were scratched.

Anyway, not a big improvement in hardness. Nevertheless just handling it, it seems hard and tough -- just a subjective impression. I don't know why that is.

It saws readily with a hacksaw. No tendency to smooth over or gum up.

It files easily, and again seems harder under the file subjectively.

Unfortunately I can't compare it to my other cast aluminum for strength and brittleness, since I don't have a similar section in those others for the vise break test. I did try some 6061 of similar thickness which seemed much tougher. But it's a good tempered extrusion alloy compared to cast, so that wasn't unexpected. The big question is, is this a better casting mix than just straight pistons?
I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #6 on: May 18, 2015, 03:16:39 PM »
Here's a reference:

http://www.aluminium.matter.org.uk/aluselect/11_castmech_browse.asp
http://www.aluminium.matter.org.uk/aluselect/13_cast_comp.asp

I was shooting for something a little like EN AC-45000

I guess unless tempered, the properties are not a whole lot different than other sand casting alloys, from the looks of it.
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Steve
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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #7 on: May 18, 2015, 03:27:26 PM »
Here's a sawn end and a broken end:

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Offline awemawson

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Re: Aluminum Copper Alloy Experiment
« Reply #8 on: May 18, 2015, 03:44:27 PM »
I last made a copper / silicon / aluminium alloy in quantity when I needed a billet to cnc cut  a new motor front / mounting plate (*) for my 2 HP Bridgeport back at the old place. To get the best out of the alloy I 'solution treated' it, It was an absolute b****r to machine and I never got a good surface finish however it worked like a dream and I'm using it to this day


http://www.bodycote.com/en/services/heat-treatment/solution-and-age/aluminium-alloys.aspx


(* I wanted a low profile 'pancake' motor as I had height constraints, and the only one I could find the previous owner had sawed the shaft and pulley off and used it and the motor front plate to fix a single phase motor on his Bridgeport, so I made a new front end and loctited a new shaft into / onto the remaining stub - amazingly it's never twisted off !)
Andrew Mawson
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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #9 on: May 18, 2015, 03:57:38 PM »
Intresting Andrew -- how much copper was in the alloy?

I just machined this mix (un-treated) and it machines well enough as is. No idea if it were hardened.

The finish is not as shiny as plain 6061, but maybe a little shinier than the high silicon piston material that I use.

I love it when a Plan B comes together!
Steve
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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #10 on: May 18, 2015, 04:01:37 PM »
Quoting from that site, Andrew, this alloy may naturally harden somewhat, as well:

Quote
Solution treating is typically performed in the 450 to 575C (842 to 1067F) range in air, followed by rapid quenching into cold water, hot water, boiling water (-T61 temper), water-polymer (glycol) solution, water spray or forced air. Natural ageing to the T4 temper will occur at ambient temperature for 2XXX, 6XXX, 2XX and 3XX alloys, with most reaching a stable temper after 96 hours. Artificial ageing in the 93 to 245C (199 to 473F) range is utilised to meet the T6 and T7X tempers.

Immediately after quenching from solution treating, all alloys are relatively soft and can be moderately formed or straightened if performed within a couple of hours. These alloys will naturally age harden at ambient temperature, with their hardness gradually increasing with time following quenching. This can be suppressed by refrigeration below about 0C (32F) if it is desired to form or straighten the material more than a couple of hours after quench. Cooling to below about minus 23C (minus 10F) or colder is required to retain the As-Quenched (AQ) temper for prolonged storage times beyond a few days.

For maximum formability prior to solution treating and ageing, these alloys must be fully annealed to produce a stable dead soft O temper by heating in the 400 to 425C (752 to 797F) range, then slow cooling (28C or 50F per hour or slower) to below 235C (455F), formed, then solution is treated and aged.
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Offline awemawson

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Re: Aluminum Copper Alloy Experiment
« Reply #11 on: May 18, 2015, 04:18:12 PM »
I  had intended to make a form of Duralumin, which age hardens, but after the event I realised that my aluminium source, like yours, being pistons had silicon in them. Copper was about 4%, silicon unknown - I supposed now that I have my alloy tester I could sample it if time permits.

(Off to visit the JCB 803 digger at the digger hospital tomorrow - I suppose I have to take hydraulic oil rather than grapes and flowers :clap: )
Andrew Mawson
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Re: Aluminum Copper Alloy Experiment
« Reply #12 on: May 18, 2015, 05:43:39 PM »
The particular alloy I was imitating is not iisted for solution treatment and aging to temper, but what the heck --  I heated a sample up with the torch, short of melting and plunged it. Now scratches 6061 t6 lightly. Will check it tomorrow to see if there is a change, how it machines, etc.
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Offline JonIndigoman

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Re: Aluminum Copper Alloy Experiment
« Reply #13 on: May 18, 2015, 06:55:17 PM »
In the past I have added copper to the soft pure aluminium at about 4% which seemed to reduce shrinkage and produce harder ingots. I don't  recall making anything with them but probably just chucked them in with other stuff cos in the early days I didn't separate my ally out into type.

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Re: Aluminum Copper Alloy Experiment
« Reply #14 on: May 18, 2015, 10:25:25 PM »
Hi John, thanks for the info.

I jumped the gun a little tonight and tried a scratch test of the heat treated piece again, and it has clearly increased in hardness in a little over 4 hours. It now clearly scratches 6061-t6 and all the aluminum samples both cast and extrusion that I've tried.

It scratches the un-treated aluminum copper alloy ingots as well.

The untreated ingots in turn will not scratch the 6061-t6 sample, so they have not increased in hardness by aging.

My conclusion is, the mix of piston material (with likely about 12% silicon) plus low silicon scrap extrusions (probably entirely 6061) to yield a probable 6% silicon content, plus the addition of 4% copper from clean anealed tubing yields an alloy which has similar hardness to 6061-t6 aluminum alloy.

Heat treatment with plunge can be used to increase the hardness of this alloy further, and aging also increases its hardness.

I'll try machining it tomorrow.
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Offline Pete W.

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Re: Aluminum Copper Alloy Experiment
« Reply #15 on: May 19, 2015, 05:34:03 AM »
Hi there, Steve & company,

This is an interesting thread.  Please forgive an  :offtopic: interruption:

My lovely but shy assistant (she's trained in horticulture, you know!) saw the photo in your first post - she thinks the flowers are potentillas.  Are they? 
Best regards,

Pete W.

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Re: Aluminum Copper Alloy Experiment
« Reply #16 on: May 19, 2015, 08:15:49 AM »
Wild strawberries, Pete.  :beer:
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Offline RobWilson

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Re: Aluminum Copper Alloy Experiment
« Reply #17 on: May 19, 2015, 08:45:25 AM »
 :proj:
Wild strawberries, Pete.  :beer:

Steve


Would the addition of strawberries to the mix make the alloy more ductile  :)

Rob

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Re: Aluminum Copper Alloy Experiment
« Reply #18 on: May 19, 2015, 08:52:39 AM »
But it would taste better  :doh:

Stuart

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #19 on: May 19, 2015, 08:53:12 AM »
 :) I'll ask Chippie, the resident chipmunk and wild strawberry expert what he thinks, Rob!  :smart:
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Re: Aluminum Copper Alloy Experiment
« Reply #20 on: May 19, 2015, 09:21:27 PM »
I milled, filed and hacksawed the hardened piece of Al/Cu today with no obvious problems, though the mill was a carbide insert type. But the fact that a hacksaw worked fine means it will probably mill okay with steel based mills as well.

It is not as hard as zamak, nor mild steel or cast iron.

Subjectively, it feels "harder" than most aluminum I cast or use from extrusion scrap. Seems that way filing. Sawing actually seems easier than gummy aluminum -- feels more "crunchy". The cutting action feels cleaner, and maybe even faster.

Milling throws small crumbs of swarf, not curls. I didn't see evidence of the aluminum tendency to weld to the tool without coolant. But it was a very small sample.

I don't know what to think of this stuff. Whether it's an advantage or not to alloy copper in my aluminum casting. Mainly because I don't have any comparison of strength to what I've normally cast in the past, and in comparison with named extrusions. If I knew it had a definite strength advantage in casting, I'd probably use it a lot.

It is clearly harder than my past castings if heat treated, but that's not necessarily a desirable quality for most of what I make from aluminum. I don't use aluminum for high wear parts, and aluminum doesn't have as good bearing qualities generally as some other metals I have on hand. Maybe it would be useful for tool holders and machine fixtures.
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Offline Will_D

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Re: Aluminum Copper Alloy Experiment
« Reply #21 on: May 20, 2015, 04:47:44 PM »
When it comes to "desigining alloys" here's a thought:

3 elements, 0.5% is the minimum addittion so we have:

200 * 199 * 198 posiible alloys! [7,880,400 combinations] I think :bugeye:

I know in over 200 years of scientific metalurgey a lot of alloys have been perfected but the numbers surely say there may be a magic alloy out there still to be discovered!
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Re: Aluminum Copper Alloy Experiment
« Reply #22 on: May 20, 2015, 10:02:06 PM »
Will, I can predict with absolute certainty, with regard to new super alloys developable but not yet tried, out of 7,880,400 possibilities, that I won't be the one doing the experiments that produce them!  :lol: :lol: :lol:

Just thought I'd try adding copper to the melt and adjusting silicon to approximate a known alloy proportion with apparently good sand casting qualities.
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Offline ironman

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Re: Aluminum Copper Alloy Experiment
« Reply #23 on: May 24, 2015, 09:33:49 PM »
I tried to dissolve copper in molten aluminium it but did not work. I used very thick clean copper wire.

 Your method of preheating copper before adding to the molten aluminium could be why my experiment did not work.

Good to see that you are experimenting with making your own alloys

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #24 on: May 24, 2015, 10:23:18 PM »
Hi ironman great to see you back!  :beer:

Well since that happened to you, I guess I should try that, too -- putting copper and aluminum together from the start.

I should also really try to cast this alu/cu mix and non-cu  piston/6061 mix metal into the same thin sections and break them to see if there seems any difference in strength. Well I guess I'll need both hardened and non hardened alu/cu as well to really tell.

Then I'd know whether it was worth adding copper or not.
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Steve
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Offline Will_D

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Re: Aluminum Copper Alloy Experiment
« Reply #25 on: May 25, 2015, 05:30:10 AM »
As the melting points are widely different the only way to get Cu and Al to alloy is by disolution.

The molten aluminium will alloy with the copper at the surface of the copper and create a eutectic. Given time and agitation the copper will sloooowly disolve into the aluminium.

The way to speed things up would be to increase the surface area a LOT so cut the copper wire into short (say = to the diameter) lengths and then see how quickly they disolve also stirring the pot will help.

PS: This is only my theory!
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Offline mattinker

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Re: Aluminum Copper Alloy Experiment
« Reply #26 on: May 25, 2015, 07:57:48 AM »
It's not only your theory! That's how it works. I used fine stranded wire when dissolving Cu into Al to make ZA12. 1%Cu, 11% Al 88% Zn by weight. 10%Cu will dissolve easily into Al.

Regards, Matthew.

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Re: Aluminum Copper Alloy Experiment
« Reply #27 on: May 25, 2015, 09:56:19 AM »
re. ZA-12:

Matt what were your feelings/results of the ZA-12 that you made? Did you make any castings with it?

The ZA-2 and ZA-3 I tried were purchased virgin alloy ingots. ZA-12 is not available easily here, and I have some pure zinc coming shortly to try different shop mized ZA numbers. But would be curious re. your results w/ZA-12.

re. al/cu:

I don't have fine copper wire, but didn't have any problem melting the copper tubing I used, folded into a couple of pellets (first photo at start of thread).

Perhaps as Ironman says it was the pre-heating that helped. I'll give here the exact procedure I followed in case it makes any difference:

First tried melting the copper, and I think it was 20+ minutes from placing cold crucible and pellets in the furnace. The crucible and pellet were glowing orange when I added a few small pieces of the 6061 to start a heel. I noticed that it immediately wetted the copper when melted (like solder). I gradually added more pieces of 6061 (low silicon Al) as it melted, then finally stuck the piston (high silicon Al) on top. It took awhile to heat up and melt -- probably 5 minutes. When I stirred it all there was no evidence of the copper pellets left, and I poured.

I wonder if preheating the copper pellets with a torch would allow them to be added after the aluminum, and still combine easily. That would save a lot of time and fuel and allow heavier section copper to be added (if they are a problem unheated). Even a mapp gas portable torch should bring a small pellet of copper up to red heat.

I also wonder if the cleanliness of the copper is a factor in getting the aluminum to wet it out initially -- like solder. Mine was clean copper tubing, and folding it with hammer also exposed bright areas.
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Offline mattinker

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Re: Aluminum Copper Alloy Experiment
« Reply #28 on: May 25, 2015, 10:10:52 AM »
I was very pleased with the ZA12 I made, it casts well in sand and machines beautifully! It has good bearing qualities. I am very lucky as here in France A lot of roofs are covered with pure zinc sheet so good quality pure stuff is available, and having done roofing work, I've been saving off cuts (drops) and scrap from dismantled roofs for years. My stash is probably worth quit a lot as scrap alone! ZA12 is supposed to have similar bearing and vibration dampening characteristics to cast Iron.

Regards, Matthew

Offline ironman

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Re: Aluminum Copper Alloy Experiment
« Reply #29 on: May 26, 2015, 01:53:54 AM »
I did do a lot of stirring to get the copper to dissolve quicker but made no difference. My thoughts were that to heat the copper up would create an oxide coating and make it difficult to dissolve copper in aluminium. It could be that I will have wait longer for the copper to dissolve. As I pour mostly iron I have not gotten back to this experiment but will give it a try in the near future.

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #30 on: May 26, 2015, 11:34:18 AM »
Thinking about it, Ironman, I bet the copper pellets were oxidized by 20+ minutes of furnace heating in an empty crucible, so my statement about clean copper probably doesn't hold water, so to speak.  :)

I'm going to have to try a few experiments to see what gives re. dissolving copper in Al.
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Re: Aluminum Copper Alloy Experiment
« Reply #31 on: May 26, 2015, 11:42:38 AM »
Thank you Matt. I will probably try some ZA-12 from purchased zinc ingot. I liked what I saw from the published specs, of ZA-12 but wasn't able to buy it, or I'd have probably used that on the lathe parts. What did you sand cast with the ZA-12?
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Offline mattinker

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Re: Aluminum Copper Alloy Experiment
« Reply #32 on: May 26, 2015, 01:00:46 PM »
What did you sand cast with the ZA-12?

I cast blocks for a "Tinker" T&G, that I didn't finish because I bought a Clarkson Mk I T&G, on which I used one of the castings for tooling.

It's very nice to work!

Regards, Matthew



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Re: Aluminum Copper Alloy Experiment
« Reply #33 on: May 26, 2015, 07:37:02 PM »
Looking forward to trying it.  :dremel:
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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #34 on: May 26, 2015, 07:44:59 PM »
re. my own copper in aluminum melt. I didn't stir it while gradualy melting the aluminum around it -- probably 10 minutes.

Are we sure that stirring actually helps?

Here's an alternate theory:

Stirring removes the highly alloyed al-cu mix adjacent to the copper -- which may have a greater affinity and actually be more active in dissolving the remainder than the unalloyed aluminum is. Stirring would remove this surrounding layer.

Just a theory.
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Offline ironman

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Re: Aluminum Copper Alloy Experiment
« Reply #35 on: May 28, 2015, 02:39:52 AM »
For me Stirring did not help, you may be right better to leave it go and do it's own thing instead of trying to speed it up.

Offline Manxmodder

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Re: Aluminum Copper Alloy Experiment
« Reply #36 on: May 28, 2015, 08:00:30 AM »
Steve,ironman, this is a very interesting topic indeed. I can see the logic in Steve's theory that stirring may be interfering with the eutectic process,but I also wonder if adding a flux after the aluminium has melted would speed up the alloying process.....OZ.
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Offline mattinker

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Re: Aluminum Copper Alloy Experiment
« Reply #37 on: May 28, 2015, 08:10:47 AM »
When I made my ZA12, I used fine stranded wire, a coincidence, but I didn't need much by weigh as it was about 1% of the finished alloy. It just disappeared into the Al. I would support Steves theory about the stirring. this is a dissolving process in a corrosive environment.

Regards, Matthew.

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #38 on: May 28, 2015, 08:37:52 AM »
Any chemists out there could probably correct my ancient high school memory of how the periodic table works, left to right, but I'm guessing Alumin(i)um would beat the pants off of Copper in a fair fight for the hand of Oxygen. That is, if it wasn't already married!  :lol:

So if that's true (highly suspect) I imagine happily oxidized copper surrounded by a vat of molten aluminum is in for a rapid divorce, flux or no. Or to put it another way, aluminum would be a flux for copper, among other things.

Please notice I'm drifting off into hated theory, and experimenting less...... :smart: :loco:
I love it when a Plan B comes together!
Steve
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Offline S. Heslop

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Re: Aluminum Copper Alloy Experiment
« Reply #39 on: May 28, 2015, 03:00:14 PM »
I'd say it depends on what the activation energy is. It's pretty much the classic thermite reaction but that famously needs a damn hot flame to get it going.

Some day i'm going to go through my old notes because i've forgotten almost all the stuff I learned at university... it makes me a pretty lousy chemist.

Offline bertie_bassett

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Re: Aluminum Copper Alloy Experiment
« Reply #40 on: May 28, 2015, 03:35:13 PM »
Please notice I'm drifting off into hated theory, and experimenting less...... :smart: :loco:

best get off the computer and into the workshop then!
a competent engineer uses the tools and knowledge available, to get a challenging job done.

 An incompetent "engineer" tells his boss that the existing equipment "can't do the job" and to get another machine

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #41 on: May 28, 2015, 10:40:59 PM »
Afraid when I'm off the computer, I'm necessarily on the tractor now. Will try to sneak some experiments in if possible.
I love it when a Plan B comes together!
Steve
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Offline awemawson

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Re: Aluminum Copper Alloy Experiment
« Reply #42 on: May 29, 2015, 07:12:23 AM »
Sounds familiar Steve - seems I'm only in the workshop to mend something or make adaptors etc. Half way through another double run of stock fencing at the moment to allow me to plant another 70 metres of native species hedging at the back end of the year.
Andrew Mawson
East Sussex

Offline awemawson

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Re: Aluminum Copper Alloy Experiment
« Reply #43 on: May 29, 2015, 08:00:55 AM »
Here's the alloy that you should be shooting for Steve:

http://www.bbc.co.uk/news/science-environment-32886000

Andrew Mawson
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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #44 on: June 03, 2015, 08:28:59 PM »
Missed that one Andrew! :beer:

I took a break after attacking a really tough stump with the Ford (and axe when I couldn't cut through some of the more hidden roots with the backhoe) and cast another piece for the lathe. This time in aluminum, because it isn't heavily loaded, but does mount the stepper motor under the ways, and it always helps to give them a nice massive aluminum plate as a heat sink to mout on.

And since I'd made some aluminum/copper alloy, I decided I might as well use that. Turned out I didn't quite have enough for the part plus sprue plus a little extra, and needed another 8 oz.

Good excuse to try another experiment in dissolving the copper in aluminum.

Last time I tried to melt the copper first, and got it and the crucibe red hot before giving up and adding small amounst of aluminum letting them melt and adding more until the full charge was in the crucible. I'd flattened the copper tubing and rolled it up to reduce oxidation when I was hoping to melt it.

This time I just tossed the piece of copper tubing into the bottom of the pot (no flattening or bending), and filled up the crucible with aluminum-copper alloy ingots plus the half 6061 and half piston aluminum to make up the 8 oz additional  I thought I'd need. This was done cold,, then placed in the furnace.

There was no problem dissolving the copper at all, though I did notice that the 6061 took longer to melt than any of the other aluminum.

I didn't stir, except just before pouring to check for any undissolved copper and to skim the dross. There was no copper tube left, and little dross. The pour went normally.

So it looks to me like:

Aluminum will readily dissolve 3/8" copper tubing without stirring, and without preheating the copper. This melt took half the time of the first one.



I love it when a Plan B comes together!
Steve
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Offline Manxmodder

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Re: Aluminum Copper Alloy Experiment
« Reply #45 on: June 04, 2015, 08:22:32 AM »
Very interesting, Steve. It's great to see this works so easily.

Alloying your own metals is a really useful discipline to learn,I've noted this for some future trials of my own.

.....OZ.

Helixes aren't always downward spirals,sometimes they're screwed up

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #46 on: June 04, 2015, 09:51:36 PM »
Thanks Oz!  :beer:
I love it when a Plan B comes together!
Steve
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Offline NormanV

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Re: Aluminum Copper Alloy Experiment
« Reply #47 on: May 16, 2017, 10:21:23 AM »
I followed this post with interest and filed it away in my memory for later use.
Now is the time! I require some material that is harder wearing than the normal alloy that I get from old wheels and thought that adding copper might do the trick. Today I melted one of my 2kg ingots and as it started to melt I added 100grammes of 20g copper wire. It took about 15 mins for the copper to completely melt and I poured it into a metal mould to produce a stick of alloy 50x25x300mm.
I read of Steve's tests of heat treating and that appears the way to go. Should I heat treat it before machining or after? I will be using HSS tools.
Norman

Offline NormanV

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Re: Aluminum Copper Alloy Experiment
« Reply #48 on: May 16, 2017, 10:45:52 AM »
I've just removed it from the mould. I have to say I was quite worried about how easily it would come out as my welding isn't up to much. I did make sure that there was draft on it but there were small gaps in the corners. I was worried that the aluminium would mould itself into it and be impossible to remove. I used polyfilla to seal the corners and much to my delight it worked perfectly. The metal fell out of the mould when I inverted it.

Offline awemawson

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Re: Aluminum Copper Alloy Experiment
« Reply #49 on: May 16, 2017, 10:48:12 AM »
You will find that it is a bit 'gummy' to machine annealed. Be aware that it will age harden as well as work harden.
Andrew Mawson
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Offline NormanV

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Re: Aluminum Copper Alloy Experiment
« Reply #50 on: May 16, 2017, 10:52:31 AM »
Ok, thanks for the quick response Andrew. When it's cooled down enough to handle I'll put it back in the kiln to heat treat it and try machining it this evening.

Offline NormanV

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Re: Aluminum Copper Alloy Experiment
« Reply #51 on: May 18, 2017, 10:15:54 AM »
Well, I did the heat treatment, I heated it until it just started to melt and then dunked it in water.
I machined it today, it cut quite well but I noticed that the surface that I achieved was not as good as the sample that Steve showed earlier in this thread. On close examination I saw that I am getting lots of tiny bubbles. I have said previously that I do not de-gas. Next time I melt some metal I will try it to see if it makes a difference for me.

Offline Biggles

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Re: Aluminum Copper Alloy Experiment
« Reply #52 on: May 19, 2017, 09:27:21 PM »
If you really want a hard alloy try Beryllium with Copper. Its used to cover expensive golf clubs and can be used for armour piercing bullets!

Offline NormanV

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Re: Aluminum Copper Alloy Experiment
« Reply #53 on: May 25, 2017, 11:15:14 AM »
I did a little experiment today, not precise but it gave a ball park comparison of the aluminium/copper alloy and the normal alloy that I use that is car wheels melted down.
I used a centre punch and a club hammer. I arranged it so that the club hammer dropped a repeatable distance onto the centre punch and then measured the resulting punch mark using a magnifier. The copper alloy gave a punch mark 1mm dia and the plain alloy 2mm dia.
I can deduce from this that the addition of copper results in a harder alloy. :)

Offline awemawson

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Re: Aluminum Copper Alloy Experiment
« Reply #54 on: May 25, 2017, 11:35:13 AM »
 :clap:
Andrew Mawson
East Sussex

Offline Pete W.

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Re: Aluminum Copper Alloy Experiment
« Reply #55 on: May 25, 2017, 03:02:54 PM »
If you really want a hard alloy try Beryllium with Copper. Its used to cover expensive golf clubs and can be used for armour piercing bullets!
 

Years ago, I had occasion to visit an aircraft company in the UK midlands.  There was a detached laboratory on the site, surrounded with a tall security fence.  Occasiomally, one or two of the staff could be seen outside the building, all clad in 'space suits'.  On enquiring of our hosts 'what's that all about?' we were told 'that's the Beryllium research department'.  My understanding is that beryllium's not very nice stuff, even alloyed (e.g. beryllium copper) or in the ceramic form (beryllia) used for semiconductor heat-sinks. 
Best regards,

Pete W.

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Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #56 on: May 28, 2017, 09:19:21 PM »
Good work Norman! And I like the sound of your test results. :beer:
I love it when a Plan B comes together!
Steve
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Offline Biggles

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Re: Aluminum Copper Alloy Experiment
« Reply #57 on: May 29, 2017, 08:09:49 PM »
I didnt realise it was that bad Pete as they have it as a coating on several things. Perhaps its the heating process and vapours that are bad. :doh:
Well done Norman, bypass Beryllium then. :headbang:

Offline Pete W.

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Re: Aluminum Copper Alloy Experiment
« Reply #58 on: May 30, 2017, 05:16:54 AM »
I didnt realise it was that bad Pete as they have it as a coating on several things. Perhaps its the heating process and vapours that are bad. :doh:
Well done Norman, bypass Beryllium then. :headbang:

Have a look here:  https://www.ccohs.ca/oshanswers/diseases/beryllium.html 

I chose that one at random from from the Google response to the phrase 'Beryllium health risks?'  There were lots more. 
Best regards,

Pete W.

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Offline Biggles

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Re: Aluminum Copper Alloy Experiment
« Reply #59 on: June 11, 2017, 01:18:31 AM »
Oh! i havent touch any that i know off. Better keep clear of that stuff then.  :bugeye:

Offline seadog

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Re: Aluminum Copper Alloy Experiment
« Reply #60 on: June 11, 2017, 05:59:49 PM »
It's used in dental plate manufacture so it's not that bad in certain applications. Dust or fumes are the real problem as I see it. We were warned back in the 70s about the risks since we had RF transistors that used Beryllia. In fact most kitchens have Beryllium present. The magnetron in your microwave cooker will have a Beryllia ceramic as the insulator. It's used because of its superior thermal conductivity.

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #61 on: June 12, 2017, 10:18:09 AM »
The use recommended against here was casting with it, or use in our home workshop, if unaware of the hazard.

If you're already in the business of making dental plates, old style RF transistors, or microwave insulators, then just ignore, you probably already know about the hazards.
I love it when a Plan B comes together!
Steve
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Offline Biggles

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Re: Aluminum Copper Alloy Experiment
« Reply #62 on: June 13, 2017, 09:57:59 AM »
 :nrocks:

Offline NormanV

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Re: Aluminum Copper Alloy Experiment
« Reply #63 on: June 21, 2017, 12:26:11 PM »
I wasn't planning on using Beryllium as I have no idea where to get it.
One thing that I have found is that aluminium with the addition of copper in the cast, machines much more cleanly whether or not given heat treatment. That will be standard for me from now on. One problem though is that it work hardens. My milling machine only has hand feed and if I go too slowly the pressure required to turn the handle increases dramatically. If I turn the feed handle briskly I find that it will cut its way through the metal quite cheerfully. This is using a 20mm cutter with a 2mm depth of cut, 15mm wide at 1000RPM on my homemade milling machine. I judge the feed rate to be 150mm per minute. Is this good or bad?

Offline vtsteam

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Re: Aluminum Copper Alloy Experiment
« Reply #64 on: June 22, 2017, 09:53:46 AM »
Interesting to hear, Norman. I haven't machined my Al/Cu recently (or anything else except a cast tractor head). Been away from the machine shop (AFMS?). But being back here reading MM and finally finished with the waterball cistern project, I'm beginning to get the machining itch again. I do wonder whether the AlCu properties have increased over time -- if aging has maade it tougher. Will have to find out soon.

Sorry, don't know what best feeds and speeds would be for this homemade stuff. But probably somebody more professional here does.
I love it when a Plan B comes together!
Steve
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