14th International Conference on Shot Peening

Effects of Laser Shock Peening-induced residual stresses on fatigue life of anodized AA 7050-T7451 components

Attolico Michele Angeloa, Casavola Caterinaa, Moramarco Vincenzoa, Renna Gildaa

Politecnico di Bari, Dipartimento di Meccanica, Matematica e Management, Via Orabona 4, Bari, Italy – micheleangelo.attolico@poliba.it

Introduction

High fatigue properties and excellent corrosion resistance are generally required in aircraft applications to ensure ideal operating conditions in harsh environments and under various and severe loading scenarios [1]. These characteristics can be provided through an appropriate combination of specifically designed surface treatments, such as Tartaric-Sulfuric Acid Anodizing (TSA) and Laser Shock Peening (LSP). The reduction in fatigue life caused by the presence of the TSA anodic layer can be effectively compensated by pre-treating the component with LSP, in order to introduce a specific Compressive Residual Stress (CRS) field and thus delay the nucleation and propagation of fatigue cracks. Previous studies have already demonstrated the validity of this strategy in the case of Shot Peening (SP) combined with anodizing treatment [2], but very few applications have specifically concerned the combination of LSP and TSA.

Objectives

In this work, the effects of the RCS field induced by an optimized LSP process on the fatigue performance of TSA anodized single edge notched (Kt>1) components (AA 7050-T7451) were investigated to verify and evaluate the fatigue enhancement determined by LSP when used as pretreatment to anodizing.