Title: Evaluation of the residual stresses and corrosion resistance of shot-peened 7075 aluminium alloy under different states
Authors: Sebastjan Žagar; Janez Grum
Addresses: Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana, Slovenia ' Faculty of Mechanical Engineering, Aškerčeva 6, 1000 Ljubljana, Slovenia
Abstract: 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 Al7Cu2Fe and MgZn2 play an important role in pitting corrosion and that the numbers and sizes of surface pits were reduced after shot peening.
Keywords: aluminium alloys; residual stresses; shot peening; pitting corrosion; cyclic polarisation; corrosion resistance; precipitation hardening; sodium chloride; NaCl; salt; fatigue cracks; crack initiation.
International Journal of Materials and Product Technology, 2016 Vol.53 No.3/4, pp.335 - 348
Received: 28 Feb 2015
Accepted: 25 Mar 2016
Published online: 22 Sep 2016 *