Youngs modulus says that for a small deformation , metals act like a spring. So your piece of cable when erected will extend in length and if you lay it on the ground it should shrink back to its natural length. Similarily for when its hot, it extends and then should shrink when it cools.
Both Cu and Al work harden so you never get springs made of these metals. Al has a fatigue limited life, thats why aircraft are stripped down and inspected because the airframe extends/contracts and vibrates a lot, so the Al can fracture due to the work hardening. Steel bridges are not stripped down because they don't fail like this, though they do rust :-(
Frank