A mechanism for the crack initiation of corrosion fatigue of Type 316L stainless steel in Hankʹs solution

Corrosion fatigue tests of Type 316L stainless steel in a simulated body fluid (Hankʹs solution) were carried out in a reciprocating bending fatigue testing machine. Corrosion fatigue cracks initiate from the attacked grain boundaries inside the pits, which are generated on the surface. The initial cracks are intergranular then change to transgranular, and the pitting corrosion and intergranular corrosion are generated alternately to initiate corrosion fatigue cracks. The multiplication and pile-up of dislocations, due to the application of cyclic stress, promote the pitting and intergranular corrosion.