what happens as a metal breaks? does the crystals of the crystal lines break? explain and make a sketch
Good question. There are many failure mechanisms, and they very with the metal and its corrosion, work hardening and fatigue history. See
http://www.jiskha.com/display.cgi?id=1268386837
for some descriptions and pictures.
A subject called dislocation theory is an important part of the story.
http://www.bondhus.com/metallurgy/body-4.htm