How to Relieve Stress in Aluminium Alloys

How to Relieve Stress in Aluminium Alloys

What is vibration stress relief?

There are many ways to relieve stress in aluminium alloys, one of the more important methods is vibratory stress relief. This non-thermal stress relief method is used in metalworking to improve dimensional stability and mechanical integrity, particularly for aluminium that has been cast, forged or welded.

The target of vibratory stress relief is residual stress, which remains after any stress-causing factors have been removed. It occurs after inelastic deformation, temperature gradients and structural changes. For example, during welding, heat causes local expansion and during cooling some areas shrink more than others, resulting in residual stresses.

Vibratory stress relief is typically used for precision parts with very tight dimensional or geometrical tolerances. It is also suitable for heavily loaded workpieces. Vibratory stress relief targets the resonant frequency of the metal in order to remove stresses. The process involves bending the aluminium with sufficient amplitude to combine the induced stress with the residual stress, which leads to plastic flow. This is how aluminium alloys are stress relieved.