"I have read it..."
Now I read it, too. I could not find the proof, but I read the advertisement.
Directionality Explained
I remember seeing photos of that chevron shape deformity in copper wires long ago but cannot locate them. However, there is this: https://www.researchgate.net/publication/245161371_Prediction_of_chevron_crack_initiation_in_inclusion_copper_shaped-wire_drawing It seems the chevrons are a result of the wire being pulled through the die and are a deformity. All the best, Nonoise |