50th Anniversary Article: The Origin and Management of Residual Stress in Heat-treatable Aluminium Alloys

The presence of macroscopic residual stresses in heat-treatable aluminium alloys can give rise to machining distortion, dimensional instability and increased susceptibility to in-service fatigue and stress corrosion cracking. This paper presents and reviews details about the residual stress magnitudes and distributions introduced into wrought aluminium alloys by the thermal operations associated with heat treatment. Experimental measurement data and the results of finite element analysis are presented and discussed. The available technologies by which residual stresses in aluminium alloys can be relieved are reviewed. The limitations of these techniques are described, and recommendations are made as to selecting the most appropriate technique to manage residual stresses. Opportunities for the future optimisation of these techniques are also presented.