Cyclic deformation and fatigue behavior of 316L stainless steel processed by surface mechanical rolling treatment

Abstract

Fully reversed strain-controlled tension-compression fatigue experiments were conducted to study the cyclic deformation and fatigue behavior of 316L stainless steel with a gradient nanostructured surface layer formed by surface mechanical rolling treatment (SMRT). The grain sizes of the nanostructured surface layer range from 30 nm to 300 nm. The SMRT significantly enhances the fatigue properties. The strain-life fatigue curve of the SMRT samples displays a distinguishable kink point which demarcates surface and subsurface fatigue crack initiations. Mechanisms associated with the enhanced fatigue property by SMRT are discussed in light of the mechanics of the gradient material and the microstructures.