MadModder

The Shop => Metal Stuff => Topic started by: vtsteam on May 18, 2015, 02:16:12 PM

Title: Aluminum Copper Alloy Experiment
Post by: vtsteam 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:

(http://www.vtsteam.com/Casting/AluminumCopperExperiment.jpg)

Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Sea.dog 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
Title: Re: Aluminum Copper Alloy Experiment
Post by: RobWilson on May 18, 2015, 02:48:34 PM
Interesting Steve  :thumbup:  how dose your new alloy machine ? 


Rob
Title: Re: Aluminum Copper Alloy Experiment
Post by: chipenter 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 .
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.

(http://www.vtsteam.com/Casting/AluminumCopperExperiment2.jpg)

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?
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam on May 18, 2015, 03:27:26 PM
Here's a sawn end and a broken end:

(http://www.vtsteam.com/Casting/AluminumCopperExperiment3.jpg)
Title: Re: Aluminum Copper Alloy Experiment
Post by: awemawson 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 !)
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.

(http://www.vtsteam.com/Casting/AluminumCopperExperiment4.jpg)
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: awemawson 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: )
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: JonIndigoman 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Pete W. 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? 
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam on May 19, 2015, 08:15:49 AM
Wild strawberries, Pete.  :beer:
Title: Re: Aluminum Copper Alloy Experiment
Post by: RobWilson 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
Title: Re: Aluminum Copper Alloy Experiment
Post by: lordedmond on May 19, 2015, 08:52:39 AM
But it would taste better  :doh:

Stuart
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam on May 19, 2015, 08:53:12 AM
 :) I'll ask Chippie, the resident chipmunk and wild strawberry expert what he thinks, Rob!  :smart:
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Will_D 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!
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: ironman 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
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Will_D 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!
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker 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
Title: Re: Aluminum Copper Alloy Experiment
Post by: ironman 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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?
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker 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


Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam on May 26, 2015, 07:37:02 PM
Looking forward to trying it.  :dremel:
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: ironman 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Manxmodder 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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:
Title: Re: Aluminum Copper Alloy Experiment
Post by: S. Heslop 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: bertie_bassett 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!
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: awemawson 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: awemawson 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

Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.



Title: Re: Aluminum Copper Alloy Experiment
Post by: Manxmodder 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.

Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam on June 04, 2015, 09:51:36 PM
Thanks Oz!  :beer:
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV 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
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: awemawson 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Biggles 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!
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV 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. :)
Title: Re: Aluminum Copper Alloy Experiment
Post by: awemawson on May 25, 2017, 11:35:13 AM
 :clap:
Title: Re: Aluminum Copper Alloy Experiment
Post by: Pete W. 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. 
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam on May 28, 2017, 09:19:21 PM
Good work Norman! And I like the sound of your test results. :beer:
Title: Re: Aluminum Copper Alloy Experiment
Post by: Biggles 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:
Title: Re: Aluminum Copper Alloy Experiment
Post by: Pete W. 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 (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. 
Title: Re: Aluminum Copper Alloy Experiment
Post by: Biggles 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:
Title: Re: Aluminum Copper Alloy Experiment
Post by: seadog 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Biggles on June 13, 2017, 09:57:59 AM
 :nrocks:
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV 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?
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam 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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 30, 2017, 04:02:14 PM
I have just cast another alloy, 90% copper 10% aluminium. I tried a file on it and it just skidded with barely a mark. It is certainly hard, will I be able to machine it? I'll find out tomorrow.
What I found interesting is the colour, with all that copper I expected it to be bronze coloured but it is silver with just a blush to it.
The copper that I used was old plumbing pipes with a few brass glands on it, so the actual composition if a bit vague.
One problem that I encountered was the low heat output of my propane torch. When I melt aluminium it normally takes approx. one hour to melt my 3kg ingots. I had thought that this was due to the size of the ingot, I have read of people having molten aluminium in 15-20 minutes.
Today I melted the aluminium first and then added the copper, from start to finish was over 4 hours! After two hours I almost gave up but by that time I had invested so much gas into the project I thought that I would see it through. I don't think that I will be trying to melt any iron with this torch.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 30, 2017, 05:48:27 PM
I was too impatient to wait until tomorrow morning so I went out at 9pm this evening to have a look at this alloy I have created. I had cast a stick 50x25x300mm. I decided to cut a piece 25mm off the end. I first tried with a hacksaw, it just skidded across the surface. So, I went back to my trusty angle grinder, the cutting disc on the grinder is somewhat worn so I was only able to make a cut 6-8mm deep around the bar, I then clamped the short piece in the vice and snapped the bar in two by hand.
Here is a photo of the break.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 30, 2017, 05:53:42 PM
What I find fascinating is that this alloy behaves nothing like copper or aluminium. Cast aluminium is quite brittle but is nothing like as hard as this. I am planning to use it as a bearing material, will it be good for this purpose? I will find out. It will definitely be better than plain aluminium or copper. What fun!
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker on October 30, 2017, 06:17:42 PM
You've made Aluminium bronze.It should be a good bearing material, it also has a high corrosion resistance.

Regards, Matthew
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 30, 2017, 06:36:31 PM
Aluminium bronze was what I was aiming for but was unsure because of the lack of the other metals that it normally contains.
It should be good for when I take my traction engine on the beach!
Title: Re: Aluminum Copper Alloy Experiment
Post by: SwarfnStuff on October 31, 2017, 01:39:44 AM
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
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 31, 2017, 06:50:29 AM
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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: AdeV on October 31, 2017, 07:17:51 AM
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]
Title: Re: Aluminum Copper Alloy Experiment
Post by: Joules on October 31, 2017, 09:47:14 AM
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
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 31, 2017, 11:33:46 AM
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.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Joules on October 31, 2017, 11:57:04 AM
The slag is dross and impurities that precipitate out of the metal to the melt/crucible wall.   I was thinking your aluminium bronze wouldn't be true, but as you created it in a steel crucible it will have pulled some iron out of the metal into the melt.   Casting molten metal into moulds is almost a chill process as the temperature drops off quite rapidly.  if you can slow the cooling to extended times you will form large or even single crystal components as in Rolls Royce turbine blades, though they have a little more trickery than just that.   Watching the big forge hammers "beat the crap out" of metal is probably the simplest way of explaining whats happening.   You are purifying the metal by squeezing out impurities that would remain in the metal and create weakness across the grain structure.  The heat allows the impurities to migrate through the metal, as when it cools they are locked in.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 31, 2017, 12:17:42 PM
Thank you Joules for taking the time to read my questions and to reply. What you say makes sense. Now I just have to translate that into action and make my metal machinable.
Title: Re: Aluminum Copper Alloy Experiment
Post by: Joules on October 31, 2017, 12:27:15 PM
Norman, as mentioned by others.  It work hardens rapidy and is really abrasive on HSS tooling.  You know when you have it wrong as the metal screams at you, and watch if you drill it, the metal is really grabby and will clamp down on a drill bit and shatter it.   LOL those have been my experiences with Ally Bronze, does make great bearings though.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on October 31, 2017, 12:39:36 PM
I've just been into the workshop and tried to drill it. After my heat treatment it seems to be harder than ever!   :doh:
At the moment it feels very disappointing, I searched for a long time to find some scrap copper. It took a long time to melt it and the result is....... difficult!
This is the problem when you experiment to try to save money, it can turn out cheaper to buy the thing that seemed so expensive in the first place.
No worries, I have learned something new and I will remember it because I did it and did not just read it.
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker on October 31, 2017, 01:41:24 PM
The answer to your question about why your alloy is not sof when cooling down after casting might be in this article.

http://mit.imt.si/Revija/izvodi/mit144/slama.pdf

The scale forming on the outside of you steel crucible looks like oxidisation.

Have fun with your traction engine on the beach!

Cheers, Matthew
Title: Re: Aluminum Copper Alloy Experiment
Post by: Joules on October 31, 2017, 02:08:06 PM
What he said above....   :thumbup:

High heat and long cool down times, in hours not minutes.

If i didn't have the furnace, it would be wrapped in stainless shim and put in the the stove with coals burning bright for 30mins+ then run the stove down slow and move the metal out of the hot zone.   Might as well do some jacket potatoes as the heat comes down.    :drool:
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on November 01, 2017, 03:17:36 PM
I put it in the furnace, heated it up to a nice red heat and then blocked the orifices. I'll leave it till the morning to cool and then see how it is tomorrow.
Title: Re: Aluminum Copper Alloy Experiment
Post by: David Jupp on November 01, 2017, 04:05:50 PM
I noticed that some of the stuff quoted mentioned a high temp solution heat treat and quench to soften, followed by a lower temp age hardening, whilst other stuff seemed to suggest a very slow cool from high temperature for softest condition.  Seems like some possible confusion here, or that things are very dependent on actual alloy composition.

If composition is not very close to a published spec, expect that you may have to experiment to find exactly what gives the behaviour you desire (perhaps limited by heat treatment facilities available).


Title: Re: Aluminum Copper Alloy Experiment
Post by: sparky961 on November 01, 2017, 09:20:00 PM
This is the problem when you experiment to try to save money, it can turn out cheaper to buy the thing that seemed so expensive in the first place.

It's taken half my life for this one to finally sink in!  I still have days where I temporarily forget.

No worries, I have learned something new and I will remember it because I did it and did not just read it.

But alas, this is why I don't regret the learning process.
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on November 03, 2017, 09:00:43 AM
This metal melting mallarky is mystifying! My first attempt at making aluminium bronze took nearly 5 hours to melt 3kg of copper plus 300g of aluminium. This produced an alloy that was almost unmachinable. Even after annealing. I decided to dilute it 50%.
I placed 2kg of aluminium in the crucible and when that was melted I added 2.3kg of my bronze. The total time to when it was ready to pour was 1hr50min. I was ready for another 4-5 hour stint!
I am waiting for it to cool down to see whether I have an alloy that will do the job.
This is such fun!
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on November 03, 2017, 09:42:49 AM
I've just tested a piece. A file cuts it and it compares quite well with steel in its resistance. It turns ok but not a great finish and it is drillable. I'm going to use it for the bearings for my traction engine which is not going to see a lot of use so it should be good enough.
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker on November 03, 2017, 09:48:30 AM
You melted the Al first in the second attempt. Molten Al is very corrosive and will dissolve copper at well below it's melting point I think you will find the melting point of your Al bronze should be just a little above that of the Aluminium.

Regards, Matthew
Title: Re: Aluminum Copper Alloy Experiment
Post by: seadog on November 03, 2017, 10:23:10 AM
I don't think it's corrosive. What does happen is that a eutectic alloy forms which has a much lower melting point than the copper.
Title: Re: Aluminum Copper Alloy Experiment
Post by: mattinker on November 03, 2017, 10:56:10 AM
I don't think it's corrosive. What does happen is that a eutectic alloy forms which has a much lower melting point than the copper.
I don't doubt you for a minut! I was told it was corrosive, but I think your explanation sounds better! I know that the resulting alloy has a lower melting point than copper. I can't find it now, but if I remember correctly, it's just a little over Al, which is very handy.
Title: Re: Aluminum Copper Alloy Experiment
Post by: seadog on November 03, 2017, 01:38:01 PM
When I was doing Engineering Science, a new A level for 1968, our teacher demonstrated this by heating a piece of copper strip whilst rubbing an aluminium rod against it. When the temperature reached the melting point of aluminium he  was able to push the rod through the copper. I don't think it reached more than a dull red heat.
Title: Re: Aluminum Copper Alloy Experiment
Post by: SwarfnStuff on November 04, 2017, 01:32:11 AM
These last few posts reinforce to me the reason I like this forum. "I learn stuff."  :smart:
   In this case it actually confirmed what I sort of knew but Eutectic was a word I failed to recall but sounded sort of familiar.
   Thanks
John B
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on November 04, 2017, 03:02:05 PM
I've had a go at making a part. It turned like cast iron with dust instead of curly swarf. It drilled but blunted the drills and it was too brittle to do anything with it.
Not a success.
Title: Re: Aluminum Copper Alloy Experiment
Post by: PekkaNF on November 04, 2017, 03:19:34 PM
Aluminium alloys can be funny. My brother told few years back about some rivets used in aeroplanes. Can't remember exactly how it went but there was a very exact heat treatmen cycle and if I remember right there was a little time, something like few hours rivets kept froxen, really cold, something like -60C just before use and riveted in very conrolled manner and then they age hardened in two hours or so to full hardness.

Pekka
Title: Re: Aluminum Copper Alloy Experiment
Post by: Meldonmech on November 08, 2017, 07:33:50 AM
 
   I have found this to be a very interesting topic, with practical experience combined with technical facts.
 I tried to produce a copper/aluminium alloy some years ago using copper wire to the melt. The percentage copper was quite small, and the difference in machined surface finish was similar. The intention was to produce duralumin but I never got round to doing any strength or wear tests.
 On my next melt, the aluminium is from the same source and I will use copper wire. From what I can remember only a small percentage of copper is required, to substantially increase the strength. I also have some small brass pipe  fittings and use some of these in a melt to compare  the results.

                                                                                                      Cheers David
Title: Re: Aluminum Copper Alloy Experiment
Post by: NormanV on November 10, 2017, 02:23:30 PM
My last post on this subject. (famous last words!)
I had cast an ingot 100x40x250mm from the 50:50 aluminium:copper mix. I took it in my workshop and dropped it half metre onto a concrete floor. It snapped in two!
I don't think that this alloy has any practical use.
I will save it to use to add small amounts of copper to future melts.
This alloying business is quite complicated!
Title: Re: Aluminum Copper Alloy Experiment
Post by: WeldingRod on February 11, 2018, 02:20:33 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!
Please don't play with Beryllium; it's toxic.  The machining award from it is too.  We use Beryllium Copper for downhill tools, and it requires special handling in the machine shop.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Title: Re: Aluminum Copper Alloy Experiment
Post by: WeldingRod on February 11, 2018, 02:24:49 PM
I have just cast another alloy, 90% copper 10% aluminium. I tried a file on it and it just skidded with barely a mark. It is certainly hard, will I be able to machine it? I'll find out tomorrow.
What I found interesting is the colour, with all that copper I expected it to be bronze coloured but it is silver with just a blush to it.
The copper that I used was old plumbing pipes with a few brass glands on it, so the actual composition if a bit vague.
One problem that I encountered was the low heat output of my propane torch. When I melt aluminium it normally takes approx. one hour to melt my 3kg ingots. I had thought that this was due to the size of the ingot, I have read of people having molten aluminium in 15-20 minutes.
Today I melted the aluminium first and then added the copper, from start to finish was over 4 hours! After two hours I almost gave up but by that time I had invested so much gas into the project I thought that I would see it through. I don't think that I will be trying to melt any iron with this torch.
My experience was that my random aluminum bronze was brass colored, quite hard, and super brittle.  I shattered some parts just getting them out of the sand.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Title: Re: Aluminum Copper Alloy Experiment
Post by: RotarySMP on February 12, 2018, 09:32:23 AM
The rivets referred to above are -DD rivets. The need to be heat solution heat treated, and come of of the heat treatment in the unstable "W" state, where they are soft, but will naturally age harden. You keep them in a chilly bin with liquid nitrogen to retard that process, long enough to insert and rivet a whole batch in a shift. They are very nice to rivet with, as they are nice and soft. They are normally only used by the manufacturers. For repairs, -AD rivets are used, which have a stable heat treat, and are a fair bit harder to drive.

With resect to aluminium bronze, this patent https://www.google.com/patents/US3378413 has an interesting line:
 With the conventional copper-aluminum-iron alloy, lower annealing temperatures in the' range of 800 to 1050 F. cannot be used because the martensitic structure transforms to eutectoid which results in a more brittle alloy having reduced strength and loss of ductility.

The present invention is based on the discovery that by adding nickel, or nickel and manganese, to an aluminum bronze alloy containing from 10 to 12% aluminum, the tendency of the martensitic structure to transform to the eutectoid is substantially suppressed. The suppression or elimination of the tendency to form the eutectoid enables the alloy to be stress relieved and permits secondary alpha precipitation at a temperature in the range of 800 to 1050 F. to thereby produce an alloy having high tensile strength and high yield strength with good ductility. The aluminum bronze alloy treated in accordance with the invention compares favorably with the more expensive cast and heat treated beryllium copper alloys.


So basically Cupper/Aluminium/Iron alloy, is probably pretty useless, as you confirmed.
Mark
Title: Re: Aluminum Copper Alloy Experiment
Post by: vtsteam on February 14, 2018, 11:39:07 PM
Photos restored after Photobucket broke the links.

Interesting re-reading this thread. Just wanted to point out that I began it by trying to compound a specific silicon and copper bearing aluminum alloy, rather than an aluminum bronze -- which is a copper alloy with some aluminum in it . Quite a different purpose and metal alloy.

The aluminum alloy I chose to try to make was EN AC-45000. Which is 6% silicon and only 4% copper. I think that was a success and it certainly machined fine. I will have to check it again now for hardness after aging a further 3 years. I did make a part for the lathe project  with it -- a base extension.

(http://www.vtsteam.com/Lathe/BedEndPiece.jpg)

(http://www.vtsteam.com/Lathe/BedEndPiece2.jpg)