An experimental study on bending fretting fatigue characteristics of 316L austenitic stainless steel

►The 316L austenitic stainless steel life of the bending fretting fatigue was much smaller than that of the plain fatigue due to the local fretting damages. With the increase in the cyclical bend stress and the number of cycles, the effects of the fretting decreased. ►The fretting fatigue cracks easily appeared at the upper fretting damage surface of the plate specimen, initiated and propagated along the direction of about 30-45° to the surface at the beginning stage. Then the crack orientation took a sudden transition in a perpendicular direction with about 72 μm. ►The fretting fatigue crack sources usually located at the plastic deformation zone beneath the white layer of fretting wear, and the crack propagation was mainly transgranular. ►A dislocation model of micro-crack nucleation mechanism in the manner of a zig-zag mode was made. With the increase in the cyclical bend stress and the number of cycles, the dislocation cellular structure transformed to twin-twin intersections.