Internal energy
All of these
During cold working process
* Grain structure is distorted
* Strength and hardness of metal increases
* Surface finish is improved
Resilience
Resilience:
Resilience is the ability of a metal to absorb energy and resist soft and impact load.
Toughness:
When a huge external force is applied on a metal, the metal will experience fracture. Toughness is the ability of a metal to resist fracture. The ability of a material to resist fracture due to high impact loads, is called toughness.
Stiffness:
When an external force is applied on a metal, it develops an internal resistance. The internal resistance developed per unit area is called stress. Stiffness is the ability of a metal to resist deformation under stress.
Hardness:
Hardness is the ability of a metal to resist permanent change of shape caused by an external force.