III.3 - Effect of Shot Peening on the Fatigue Strength of 2024-T3 Aluminum Alloy in the Unwelded and Welded Conditions

Abstract

Aluminum and aluminum alloys are widely used materials in construction and design of machine parts due to their high strength-weight ratio and their good resistance to wear and corrosion. Aluminum alloy 2024-T3 is a widely used material in the aircraft industry. It is used in the as-received condition (un-welded). The possibility of using this alloy in the welded condition widens its use and applications in the aircraft and automobile industries. However, the restrictions of its use in the welded condition are due to its liability to stress corrosion cracking and its poor fatigue strength. This chapter investigates the use of aluminum alloy 2024-T3 in the welded condition. The effect of shot peening on the improvement of fatigue strength and fatigue life of this alloy in the welded condition is also discussed. Two types of welded joints are also reviewed, the butt single-U and the double Vee. The effect of the shot peening intensity on the fatigue strength and fatigue life of these two welded joints is also investigated. It has been found that for both joints, the fatigue strength and life were improved, and that the improvement increases as the shot peening intensity increases. Furthermore, it was found that the butt single-U welded joint has higher fatigue strength and life than the double Vee welded joint.