Evaluation of the residual stresses and corrosion resistance of shot-peened 7075 aluminium alloy under different states

摘要

This paper investigates the effect of pitting corrosion and residual stresses on different shot-peened ENAW 7075 aluminium alloys under different states. The objective of the research was to establish the parameters of the shot peening treatment of the aluminium alloy in different precipitation-hardened states concerning residual stress profiles and corrosion resistance. The experimental characterisation is primarily based on the evaluation of the residual stress profiles caused by shot-peening treatments and on the measurement of corrosion potentials as well as of cyclic polarisation curves in an NaCl solution for different material conditions. The obtained results show a favourable influence of shot peening treatment on induced compressive residual that retarded the initiation of fatigue cracks. The analysis also indicated that particles such as Al_7Cu_2Fe and MgZn_2 play an important role in pitting corrosion and that the numbers and sizes of surface pits were reduced after shot peening.