Effect of post-quench delay on stress relieving by cold compression for the aluminium alloy 7050

The objective of this investigation was to determine the influence of post-quench delays on residual stresses in the heat treatable aluminium alloy 7050, when stress relieved by cold compression. Immersion quenching after solution heat treatment introduces high magnitude residual stresses. These residual stresses can be relieved by the controlled application of post-quench plastic deformation. The effect of a delay between quenching and the application of cold compression has been investigated. During this delay, the aluminium alloy undergoes natural aging, which changes the workhardening behaviour of the alloy during subsequent cold compression. Neutron and X-ray diffraction were used to characterise the residual stresses. It was found that reducing the post-quench delay resulted in lower magnitude residual stresses after cold compression.