Influence of quenching and aging on residual stress in Al–Zn–Mg–Cu alloy 7449

Abstract

This investigation aimed to quantify the size and distribution of residual stresses remaining in rectilinear aluminium forged alloy blocks after they had been partially and fully heat treated. Various quench conditions were used including water at different temperatures and poly oxyethylene glycol (PAG) in two concentrations. The influence of standard and novel aging procedures including retrogression and reaging has been determined. Residual stresses were characterised using x-ray and neutron diffraction. Residual stress magnitudes were found to vary significantly with rapidity of cooling from the solution treatment temperature with the subsequent aging treatments having a much smaller effect. The influence of the heat treatments on mechanical properties of the alloy was predicted by means of quench factor analysis and measured using indentation hardness and tensile testing. Quench factor analysis is also used to predict the change in lattice parameter arising from different quench paths in the strain free reference samples (d 0 ).

Two-Dimensional Mapping of In-plane Residual Stress with Slitting

“…Neutron diffraction could be used in a similar way, but with that method's larger sampling volume providing a thickness-averaged, rather than near surface, measurement. Some interesting measurements of quenching residual stress in thick aluminum bars were made using two diffraction techniques [3]. Those measurements comprise a very basic map of stress along three orthogonal lines, and because the measurements were in large parts they demonstrate the significant time and care required to form a map using diffraction.…”

Effects of Post-Sinter Processing on an Al–Zn–Mg–Cu Powder Metallurgy Alloy

“…In standard T6 (i.e., Sol-Age) processing, it is well documented that 7xxx series aluminum alloys will have compressive residual stress within the surface of the part instilled by quenching after solution heat-treatment [32,33]. Such stresses are beneficial to fatigue behaviour, as they act to resist in-service tensile loads.…”

Influences of residual stresses and initial distortion on springback prediction of 7B04-T651 aluminium plates in creep-age forming

“…The material is subjected to solution heat treatment at temperature for soaking time and then quenched to room temperature ( 0 ) to produce a supersaturated solid solution. After stretching at 0 for stress relief and first-stage-ageing at to make the microstructure stable, the residual stresses within the aluminium plate is very low, normally about 15 MPa in both the rolling and transverse directions (Prime and Hill, 2002;Robinson et al, 2012). Figure 1.…”