Necking (engineering)

Occurs in the tensile test after reaching tensile strength ductile materials, a local constriction, then the break occurs in the region.

The thereby occurring largest relative change in cross section is called the reduction of area; it is a measure of the ductility of the material:

With

• The initial cross -sectional area of the unloaded test bar
• The smallest cross-sectional area of the broken rod, that is, the residual cross- sectional area at the constricted position.

Photo of a ductile fractured tensile specimen

End view of a cylindrical specimen ( Al-Mg- alloy ) to ductile fracture

• Material property