Originally Posted by
rpenmanparker
Isn't that how fatigue happens? Even to plastic? Just like steel, nylon is semi-crystalline. The crystals provide strength and stiffness. The amorphous regions provide ductility. Flexing the material (working it) causes crystallization at the flex point which results in brittleness due to the loss of amorphous material. Hence fatigue failure.
Uhh... no. Work hardening is a specific treatment to malleable metals, and is used to increase strength and rigidity, not to induce fatigue or cause failure. Apples and oranges, my friend.