Very high-cycle fatigue resistance of shot peened high-strength aluminium alloys

Abstract

The present paper is aimed at investigating the effect of two shot-peening treatments on the plain and notch fatigue behavior of the Al-7075-T651 alloy. The Wöhler S-N curves were determined by pulsating bending for the different experimental conditions exploring fatigue lives comprised between 105 and 108 cycles. It was found that improvement in plain fatigue resistance due to shot peening steadily declines during fatigue life. Conversely, the reduction in notch fatigue sensitivity due to shot peening is more pronounced in the very-high cycle fatigue regime. Scanning Electron Microscope (SEM) fractography revealed a tendency towards sub-surface fatigue crack initiation. The extent of the residual stress redistribution during loading was investigated by means of X-ray Diffraction measurements. © The Society for Experimental Mechanics, Inc. 2013.