Optimisation of the fatigue resistance of 2024-T351 aluminium alloys by controlled shot peening—methodology, results and analysis

A methodology dedicated to the optimisation of the fatigue properties of aluminium alloys by controlled shot peening is presented. Selection of the peening conditions is made out of the use of the Design of Experiment and the Effects Neutralisation Model. Both techniques allowed the optimisation both in terms of life and crack growth rates. Experimental determination and further analysis of the residual stress relaxation patterns revealed that at high stress levels, low cycle fatigue, life improvement is predominantly due to slow crack growth rates, while in high cycle fatigue the extension of life is attributed to a prolonged period of crack arrest.