Explanation
The shape and size of the same body change under the action of external force. If the external force is canceled, the shape and size will recover, that is, deformation is reversible, which is called elasticity; When the external force exceeds a certain limit, the effect of external force will be canceled, and the shape and size of the deformed material will not be restored, resulting in permanent changes, which is called plastic deformation.
Classification
Fundamental of Material Science -> Structural basis of materials