Quote:
Originally posted by koslov
Since87, if your copper is already annealed, why not test it, then pound and bend it, and test it again? I wouldn't know how to make a strip that small, and I don't have any work-hardened C102 left.
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The sheet copper is in the form of 0.5 m X 1 m sheets and I don't have a good way of cutting it off without at least somewhat work hardening it in the process.
I decided to test the easy way instead. I took about six foot of 22 gauge magnet wire, put an Amp through it with a current source, and measured the voltage across it. I then wrapped the wire around a pencil and unwrapped it about 5 times to work harden it, and measured the voltage drop again.
The resistance of the work hardened wire was 107.0% of the resistance of the unworked wire. Some of the increase of resistance may have been due to a bit of stretching of the wire as I wrapped it, but I'd guess that was under 1%. (Can't measure a change in length, since the worked wire is all kinked up.)
I think the most accurate and useful test would start by measuring the resistance of a hard piece and then annealing. This would minimize any mechanical changes to the piece. I do think the test I did, indicates that a gain of significantly more than 3% in conductivity may be attainable through annealing.