What is the difference between Cast Iron and Ductile Iron?

What is the difference between Cast Iron and Ductile Iron?

Ductile Iron is a newer stronger material, created by the addition of magnesium alloy to the molten iron. If a material can withstand extensive deformation without failing under high tensile stress, it is considered ductile.The result is an iron that is much stronger and harder to break, more corrosion resistant, and is easily machined.