Toughness and Impact Strength

Toughness:

Toughness is a measure of the amount of energy a material can absorb before actual fracture or failure takes place. The toughness of a material is its ability to withstand both plastic and elastic deformation. “The work or energy a material absorbs is called modulus of toughness”

For Ex:

If a load is suddenly applied to a piece of mild steel and then to a piece of glass the mild steel will absorb much more energy before failure occurs. Thus mild steel is said to be much tougher than a glass.

Impact Strength:

The resistance of the material to fracture under impact loading, i.e. under quickly applied dynamic loads. Two standard tests are normally used to determine this property.

1. The IZOD impact test.

2. The CHARPY test.