Quote:
Originally Posted by
SalsaPodio 
You aren't really plastically deforming the Cu unless you bend the cable quite a bit. Therefore you aren't creating any dislocations.
Considering you are using drawn wire, there are already a massive amount of dislocations present, not to mention the low stacking fault energy of Cu, which gives it a huge propensity for twinning. 
Standard practice is to take a 0.1% offset as the plastic instability, although plastic deformation usually occurs before that.
http://en.wikipedia.org/wiki/Yield_(engineering)
Quote:
Originally Posted by
SalsaPodio And I'm not sure where you are getting that info, but between coarse grained Cu and nanocrystalline Cu there is about an order of magnitude difference in the conductivity, not 2.
Just look at this paper about differences in conductivity due to twinning in nanocrystalline Cu
http://www.synl.ac.cn/org/mat/llu/PDF/japchen201006010686.pdf
Hibbard et al, 1958. Strain is different from grain size.
Grain size has a much smaller effect though .. only 2-3 times versus 1/d.
Edited by cegras - 4/19/11 at 10:21pm
