Effect of Ultrasonic Impact Surface Modification on the Mechanical and Corrosion Behaviors of 316L Stainless Steel

Herein, the effect of ultrasonic impact (UI) surface modification on the mechanical and corrosion behaviors of 316L austenitic stainless steel is studied. Taking into account the simulated seawater corrosion, three groups of specimens referred to as 316L(Untreated), 316L(UI), and precorroded 316(UI) are prepared. The mechanical properties of the precorroded 316(UI) specimens are investigated, and the fatigue fracture mechanism of the UI surface‐modified specimens is revealed. The results indicate that the corrosion resistance of 316L(UI) is greatly improved. Compared with 316L(UI), the tensile strength of the precorroded 316L(UI) is 695 MPa with a decrease of 1.13%, and the fatigue strength of the precorroded 316L(UI) is 250 MPa with a decrease of 1.96%. As the stress range decreases, the cracks in the precorroded 316L(UI) originate from the surface. The average tensile stress and surface integrity jointly determine the location of the cracks’ initiation.