Material can be classified as either being ductile or brittle , depend on stress-strain characteristic.
Ductile Material.
Any material that can be subjected to large strain before it fracture is called a ductile material. One way to specified the ductile of a material is to report its percent elongation or percent reduction in area at the time of fracture. It the specimen ‘s original gauge length is L0 and its length at fracture is Lf then ,