Effect of the Shot Peening Surface Treatment on the Corrosion Behavior of 2024-T3 aluminum alloy

The aim of this work is to study the effects of mechanical surface treatment using shot peening (SP) with different time to solve the problem of corrosion rates in Aluminum Alloys (2024-T3) in sea water 3.5% NaCl Solution. The shot peening (SP) parameters are; the diameter of steel ball was 2.75 mm with hardness of 55 HRC, angle of nozzle was 10°, the distance from specimens surface to the nozzle was 120 mm and shot peening time at 15, 25, 35, 45, and 55min. Microstructure, residual stresses, surface roughness and micro-hardness were examined. All specimens were prepared for Corrosion test according to specification standard of ASTM G71-31with the dimensions of (15*15*3) cm. Corrosion test was also carried out by electrochemical methods for all specimens in sea water, and calculated rate of corrosion by using Tafel extrapolation method. The results shown that the appropriate affection of shot peening times on corrosion rates as generation of compressive residual stresses was effect to increase of metal surface hardness with decrease in corrosion rate.