Time dependent hardness and residual stress reduction in a shot-peened aluminum alloy 2024-T351

Abstract In common engineering practice, the shot-peened aluminum alloy 2024-T351 is often subjected to loading. After time passes, the residual stress induced by shot peening might relax leading to respective metal cracking and failure. For this study, samples were stored for two years and a comparison of the hardness and microstructure before and after two years storage was carreid out. The primary aim of this study was to determine the effect of time on hardness and microstructure of shot-peened sample, thus to calculate the residual stress relaxation depending on time parameter. The results showed that the hardness and the residual stress of the material reduced after two years. The average reduction of the hardness is 20 % and the residual stress reduction ranged at 47 %