Roughness, Residual Stresses and Pitting Corrosion Effect on Shot

Original scientific paper The paper deals with the effect of roughness, residual stresses and pitting corrosion on different shot peened (SP) ENAW 7075 aluminium alloy in different states. Suitable residual stress profile increases the applicability and life cycle of mechanical parts, treated by shot peening. Pitting corrosion has a major influence on aging of structural elements made of high strength aluminium alloys as corrosion pits lead to earlier fatigue crack initiation under tensile dynamic loading. In order to improve material resistance to corrosion fatigue it is necessary to reduce pit-tip stresses. To eliminate or reduce pit stresses, shot peening was proposed. The objective of the research was to establish the optimal parameters of the shot peening treatment of the aluminium alloy in different precipitation hardened states with regard to residual stress profiles and corrosion resistance. The analysis indicated that particles such as Al7Cu2Fe and MgZn2 play an important role in pitting corrosion and after SP the number and size of surface pits was reduced.