Mechanisms of Overload Retardation During Fatigue Crack Propagation

Abstract

The effect of single overloads on room-temperature fatigue crack growth has been studied in two steels of markedly different yield stresses. The observed retardation effects have been presented and the evidence suggests that overload retardation is primarily due to residual compressive stresses generated in the crack tip region, and associated with crack closure effects. The results have been rationalized in terms of a fatigue crack growing through overload plastic zones of different shapes and sizes associated with plane stress and plane strain deformation.