Plastic deformation in metal causes it to change shape, usually under stress such as a spinning turbine vane. Ceramics cannot deform, they are too hard and would shatter.

Plastic deformation of metals above the recrystallization temperature.

it is deformation below recrystalization temperature.

Plastic deformation is a permanent unrecoverable deformation. When the load that caused the deformation is removed, the material will not return to it's original shape but will maintain it's newly deformed shape.

A moving die, or forming-tool, presses into a sheet of metal and against a fixed die. The metal undergoes what is known as plastic deformation to take on the desired shape and thickness.