Low-cycle fatigue behavior of gradient structured austenitic stainless steels under high strain amplitude

The present work focuses on the investigation of low-cycle fatigue performance of gradient structured (GSed) 316 austenitic steels under high strain amplitude loading conditions. The results show that GSed steels exhibit inherently lower fatigue life than their coarse-grained counterparts. The analyses using energy-based criterion reveals that the fatigue life decrement for GSed steels is attributed to the reduced capability of damage accumulation and the lack of ability to effective damage diffusion. The former is due to the worsened plastic deformation potential and the latter to the degraded surface plastic deformation uniformity.