I have a good friend that used to have the memory metal frames. He was very fond of doing that 180 degree bend demo too. Until the day he did that and the snapped right in half. One of the welds broke on the bridge piece. I'm afraid I laughed out loud when that happened. I had been making metal fatigue jokes since he got them.

Now it may have been way too many cycles that built up to that, but they CAN be broken... :-)

They are very tough though.