Strain-Controlled Fatigue Behavior and Microevolution of 316L Stainless Steel under Cyclic Shear Path

Abstract

Based on the twin bridge shear specimen, the cyclic shear experiments were performed on 1.2 mm thin plates of 316L metastable austenitic stainless steel with different strain amplitudes from 1 to 5% at ambient temperature. The fatigue behavior of 316L stainless steel under the cyclic shear path was studied, and the microscopic evolution of the material was analyzed. The results show that the cyclic stress response of 316L stainless steel exhibited cyclic hardening, saturation and cyclic softening, and the fatigue life is negatively correlated with the strain amplitude. The microstructure was analyzed by using electron back-scattered diffraction (EBSD). It was found that grain refinement and martensitic transformation during the deformation process led to rapid crack expansion and reduced the fatigue life of 316L.

Effect of an Orthogonal Locking Plate and Primary Plate Working Length on Construct Stiffness and Plate Strain in an In vitro Fracture-Gap Model

“…Our results infer that orthogonal plate application may extend primary plate fatigue life. [32][33][34] We accepted the second research hypothesis since stiffness was inversely related to working length in both bending and torsion, and strain was directly related to working length. There was a significant incremental reduction in bending stiffness as working length was extended for the single plate constructs.…”

“…10,12,14,[29][30][31] Lower strain in the orthogonal plate constructs should result in longer implant fatigue life. 32 The fatigue life of a material is inversely proportional to the stress applied with each cycle and stress is directly proportional to strain within the elastic modulus of a material. 24,[33][34][35] Stress can therefore be computed for a specific region of interest if strain is known.…”

“…10,12,28 The fatigue life of the implants was not directly assessed; however, through direct strain measurement and subsequent stress calculation, inferences can be made regarding implant fatigue life. [32][33][34] We selected fourpoint bending to produce a constant bending moment across the entire construct during loading to allow comparison between constructs of varied stiffness. Nondestructive testing does not provide information about the yield load and ultimate strength of the constructs.…”

Special Issue “Fracture Mechanics and Fatigue Damage of Materials and Structures”

“…Based on the twin bridge shear specimen, Xinna Liu et al [2] performed cyclic shear experiments on 1.2 mm thin plates of 316L metastable austenitic stainless steel with different strain amplitudes from 1 to 5% at ambient temperature. The fatigue behavior of 316L stainless steel under the cyclic shear path was studied, and the microscopic evolution of the material was analyzed.…”

Enhanced Fatigue Limit in Ultrafine-Grained Ferritic–Martensitic Steel

“…It is known that understanding the mechanisms for the enhancement of fatigue endurance is important for fundamental and practical applications [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. The characteristics of the fatigue failure of metallic materials are determined by many factors, among which grain boundaries, dispersed particles, and solid-solution hardening play an important role [ 3 , 10 , 11 , 12 , 13 , 14 ].…”