Fracture modes encountered following the application of a major tensile overload cycle

• Published in: International journal of fatigue Vol. 15; no. 1; pp. 53 - 60
• Main Authors: Damri, D., Knott, J.F.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1993; Elsevier Science
• Subjects: Applied sciences; cleavage fracture; Exact sciences and technology; Fatigue; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; tensile overload; transient retardation; void growth; tensile overload; transient retardation; void growth; cleavage fracture; Cleavage fracture; Propagation velocity; Overload; Low carbon steel; Mechanical properties; Carbon steel; Structural steel; Void; Experimental study; Fatigue fracture; Fatigue crack; Crack propagation
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/0142-1123(93)90078-5

Monotonic modes of failure, induced at the fatigue crack tip by application of a major tensile overload cycle, have been studied in a low-carbon structural steel. Tests were performed on fatigue cracks grown at a load ratio of 0.6 and a constant baseline stress intensity range corresponding to fatigue crack growth rates in the Paris regime. Both void growth and quasi-cleavage fracture were observed at the overload location. The quasi-cleavage fracture was associated with increased post-overload fatigue crack growth rates, prior to the occurrence of a transient retardation of the growth rate. A residual compressive stress field, generated by the overload cycle, ahead of the blunted crack tip was considered to be the primary mechanism responsible for the retardation phenomenon.