Thx 8-ball for digging into this!!! Very informative.
One question, all this talk about 'cold working' copper decreasing thermal conductivity does it really apply to the extent suggested at the start of the thread? What I mean. Most of what we do to a piece of copper is to a surface. We are not bending, skieving, or compressing to an extent that would cause significant deformation. Yes the surfaces will be deformed to some depth depending on the method used. But the bulk of the mass will not have sufficient stress applied to cause crystal deformation. Or am I out in left field?
Since most copper bar stock people buy is of the cold drawn type I think annealing would be good at some point during the making of a WB. I guess my question is do you have to wait until it's complete (except for final lapping) before you anneal and to what extent machining and lapping will actually have on thermal conductivity?
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