DEFINITIONS

• Elastic means it will return to its original size and shape once any deforming force is removed.
• Plastic means it doesn`t even begin to return to its original shape after a deforming force is removed e.g plastacine.
• Ductility is the ease with which it can be be reshaped by applying forces on it.

MOLECULAR EXPLANATIONS

• Ductile materials, like metals can be foreced to take up new shapes by the application of force. This is because the regular metallic bonding allows the atoms to move and bond with different atoms much easily.

Notes:

• Materials do not necessarily behave the same under compression as stretching forces, for instance crack propagation is much harder under compression.