Difference between Resilience and Toughness?

Resilience in metals is a term used to describe the ability of a metal to return to its original shape after it has been deformed. The resilience of metals is measured by using the Vickers hardness test which is based on indentation strength and hardness.

The harder and tougher the material, the greater its resilience. Metals such as steel have high resistance to deformation and so they are considered very resilient. 

Resilience in metals is the ability of a metal to absorb energy from an external source and still maintain its original shape. For example, if you have a piece of steel that has been hit by a hammer, it will not lose its original shape but rather retain the form of the piece of steel. The reason for this is that resilience does not require any significant amount of force to be applied to a metal.

Metals such as aluminum and copper are less resistant and hence they have low resilience or plasticity. 

Soft metals like lead or tin become brittle under pressure because they do not retain their shape when subjected to stress.

Resilience in metals is a phenomenon that occurs when the yield strength of a metal decreases below its yield stress.

The yield stress for metal is defined as the maximum tensile stress to which it can be subjected without failing. The yield strength is the ultimate tensile strength, which is used to determine whether or not the material has failed under tension.

Toughness is the ability of a material to resist breaking or deform under load. 

Toughness is the ability of a material to withstand high pressure, strain, and temperature. It is measured in terms of its resistance to permanent deformation under normal operating conditions (low-temperature operation). The resistance can be determined by using mechanical testing methods like indentation, compression, or shear tests.

A material with high toughness is less likely to fracture or break when subjected to a large force. 

 Steel, which has high toughness, will deform under pressure but not shatter like aluminum would. The ideal alloying element for steel is chromium (Cr), while copper and nickel are required for making stainless steels with low thermal expansion coefficients and good corrosion resistance at high temperatures. 

The hardness of metals is dependent on their atomic structure, which determines the crystal lattice they form when they are solidified. However this doesn't mean that all metals have similar hardness values. For example aluminum has a relatively low hardness but it's also one of the most ductile metals available because it is mostly used for fabrication and molding processes as well as aerospace engineering.