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.

DOI: 10.1504/IJMPT.2016.079195

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 *

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