If you have any problems related to the accessibility of any content (or if you want to request that a specific publication be accessible), please contact us at firstname.lastname@example.org.
Fatigue behavior of 316L stainless steel plate specimens with two opposing surfaces processed by surface mechanical rolling treatment
AltmetricsView Usage Statistics
Surface mechanical rolling treatment (SMRT) was used to fabricate a gradient nanostructure on the surface layers of 316L stainless steel plate specimens which were then subjected to fully reversed strain-controlled tension-compression fatigue experiments to study the fatigue behavior. SMRT is a surface process utilizing repeated and deep rolling at a high strain rate, which results in a nano-grained thin layer near the surface of the processed workpiece. The plate specimen has a cross section of 7.0mmx5.5mm, with only two opposing surfaces processed by SMRT. The grain sizes of the nanostructured surface layer range from 30 nm to 300 nm while the coarse-grained base material has an average grain size of 70 μm. The stress-life fatigue curves show a significant enhancement of fatigue strength due to the surface process. The strain-life fatigue curve of the plate SMRT specimens is practically identical to that of the base material, which is very different from previous studies where round SMRT specimens were tested. When a strain amplitude is lower than 0.4%, fatigue cracks are found to initiate in the base material. Cracks are initiated in the SMRT layer when the strain amplitude is higher than 0.4%. Unlike round specimens where the strain-life curve displays a distinguishable kink point at the demarcation strain amplitude of 0.4%, the strain-life curve of the plate specimens does not clearly show such a kink point. The difference between the results of the round specimens and those of the plate specimens is attributed to the difference in stress state. The results of the current study confirm the fatigue mechanisms of a component consisting of materials of different fatigue properties.