Ductility involves determining the extent by which a material can withstand plastic deformation without rupture.
Bend test for ductility provides a simple way to evaluate the quality of materials by their ability to resist cracking or other surface irregularities during one continuous bend. With a ductile fracture, there is a considerable amount of plastic deformation prior to failure. In metals, for example, the fracture shows a typical cone and cup formation, and the fracture surface appears rough and fibrous. Ductile materials show a measured amount of plastic deformation prior to fracture.
Typical graph showing ductility test: