Metal stretching, heat and hysteresis

[Zman]

Stretch piece of metal within its elastic limit and it cools down.
Does it cool down for the same reason that a gas cools down when expanded?

But if the piece of metal is repeatedly stretched and released (like with a spring), I am led to believe that it heats up, although I am not sure.
I know that the process of cycling the metal within its elastic limit is not 100% efficient, and this is due to hysteresis. So whether repeatedly stretched or compressed, I would expect the metal will heat up.

 

[npsmith514]

Right track

When you stretch a spring it will cool down a small amount like you think for a fairly similar reason as a gas, essentially boiling down to a constant amount of energy existing in a larger space.

you are also correct that the model you described above is a "perfect" model. Although this is often assumed to be 100% efficient for metals, this is never true and some heat is generated.