Define the difference between elastic and plastic deformation in terms of the effect on the crystal lattice structure.

Elastic Deformation:

Elastic deformation is due to the elasticity of the body i.e., the deformation disappears on removal of external forces and the lattice regain its original structure.This type of deformation is temporary  in nature.This type of deformation depends mainly on the chemical bonding of the substance. It occurs due to bending or stretching of chemical bond under applied stress where atoms do not slip pass over each other.It is a reversible process.

Plastic Deformation:

Plastic deformation is due to the plasticity of the body i,e., the structure can be easily shaped or molded . This type of deformation is permanent  in nature.This type of deformation occurs mainly due to breakage of chemical bonds(limited in number) between constituent atoms.Atoms may slip pass each other causing dislocation of atoms , resulting in permanent deformation even after stress is removed. It is an irreversible process.