A study on fatigue damage and crack initiation in austenitic steel matrix during very high cycle fatigue
Guocai Chai
Abstract
Fatigue damage and crack initiation behavior has been studied in an austenitic stainless steel using a novel progressive stepwise load increasing method with a cycle step greater than 108 cycles and investigated with a FIB-SEM. Subsurface crack origin with a fine granular area in the matrix was formed. Heterogeneous plastic deformation causes strain localization and grain fragmentation. Localized plasticity exhaustion induces crack initiation. A crack origin is completed once a short crack reaches the stress intensity factor threshold for stage II crack propagation. This study provides a fundamental discussion how damage and crack initiation in matrix occur during very high cycle fatigue.
Topics & Concepts
Materials scienceCrack closurePlasticityFatigue testingAusteniteStress concentrationFracture mechanicsLow-cycle fatigueCrack growth resistance curveComposite materialStress intensity factorDeformation (meteorology)Structural engineeringMetallurgyMicrostructureEngineeringFatigue and fracture mechanicsMicrostructure and Mechanical Properties of SteelsHydrogen embrittlement and corrosion behaviors in metals