ABYMC

castingisfun · Posted: Mon Dec 28, 2009 3:18 am Post subject: brittle AL?

I recently was recycling some computer CPU heat sinks. These had a 1" dia by 1/2" deep copper insert in them. The insert got eaten up (disolved) way faster than I expected. Is this aluminum going to be too brittle for anything?

T3sl4 · Posted: Mon Dec 28, 2009 6:16 am Post subject:

Any guess on percentage?

More than 5% copper will be noticably harder and more brittle (and probably also flow worse and corrode more, since that's what copper alloys are known for..). More than 10% and it's going to be on the weak side.

I've made 50% master alloy, and it's quite brittle indeed.

Tim
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castingisfun · Posted: Mon Dec 28, 2009 9:24 pm Post subject:

It's hard to say. I had a few of those heat sinks and I only recovered two of the copper cores after they slipped free of the solid aluminum. I also had misc extruded AL in the pot. Oh well, I'm not making bridges. Since then, I acquired some transmissions and have kept the tranny ingots seperate.

BlueFlame · Posted: Thu Feb 25, 2010 7:28 pm Post subject:

This reminds me of the dozens of hard drives I've smashed over the years. They're made of some sort of brittle aluminum alloy that shatters under a hammer blow for easy...err.. disassembly. I never found out the alloy, but the casted stuff never gave me a problem.
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