Stress-relaxation viewpoint to study the room-temperature cyclic deformation behavior of a low-density steel

• Published in: International journal of fatigue Vol. 139; pp. 105673 - 7
• Main Authors: Moshiri, A., Zarei-Hanzaki, A., Anoushe, A.S., Abedi, H.R., Mirshekari, B., Berto, F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-10-2020; Elsevier BV
• Subjects: Cyclic hardening; Cyclic loads; Deformation; Dislocation density; Dislocation mobility; Dislocations; Dynamic strain aging; Materials fatigue; Precipitation hardening; Room temperature; Steel; Strain controlled fatigue; Stress relaxation; Cyclic hardening; Steel; Strain controlled fatigue; Dislocations
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2020.105673

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•Proposing a new method to diagnose the micro-mechanisms of cyclic deformation.•For the first time, merging the dwell-fatigue and stress relaxation concept.•Recognition of dynamic strain aging through room temperature dwell-fatigue.•Diagnosis of different dislocation response to tensile and compressive half-cycles.
A novel method is offered with the task of unveiling the underlying micro-mechanisms of cyclic deformation. This method by merging of dwell-fatigue and stress relaxation concept provides the capability of assessment of the dislocation response to cyclic deformation and subsequently the differences between tensile and compressive half-cycles behavior. Interestingly, the apparent activation volume and mobile dislocation density have been successfully calculated in the course of cyclic loading. Noteworthily, room-temperature dynamic strain aging is firmly proved through these novel findings in a cyclically-loaded lightweight steel. This promises to be a breakthrough in deep understanding the behavior of materials under cyclic loading.