Internal stress/strain analysis during fatigue crack growth retardation using neutron diffraction

Sukho Seo, E-Wen Huang, Wanchuck Woo, Soo Yeol Lee*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Fatigue crack growth retardation of 304 L stainless steel is studied using a neutron diffraction method. Three orthogonal strain components(crack growth, crack opening, and through-thickness direction) are measured in the vicinity of the crack tip along the crack propagation direction. The residual strain profiles (1) at the mid-thickness and (2) at the 1.5 mm away from the mid-thickness of the compact tension(CT) specimen are compared. Residual lattice strains at the 1.5 mm location are slightly higher than at the mid-thickness. The CT specimen is deformed in situ under applied loads, thereby providing evolution of the internal stress fields around the crack tip. A tensile overload results in an increased magnitude of the compressive residual stress field. In the crack growth retardation, it is found that the stresses are dispersed in the crack-wake region, where the highest compressive residual stresses are measured. Our neutron diffraction mapping results reveal that the dominant mechanism is by interrupting the transfer of stress concentration at the crack tip.

Original languageKorean
Pages (from-to)398-404
Number of pages7
JournalKorean Journal of Materials Research
Volume28
Issue number7
DOIs
StatePublished - 1 Jul 2018

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