| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 776895 | International Journal of Fatigue | 2013 | 8 Pages |
•Precipitate cutting may affect the fatigue crack growth rate for SUH660 steel.•A dislocation accumulation model is proposed for the crack tip in SUH660 steel.•The model is based on back stress behavior.•Buff-polish causes acceleration of crack growth for the non-strained specimens.•Buff-polish enhances plasticity-induced crack closure for the pre-strained specimen.
Precipitation particles in precipitation-strengthened materials are considered to be cut by pre-strain treatment, which affects the fatigue strength. In this study, fatigue tests were performed on precipitation-strengthened stainless steel SUH660 to investigate the effect of pre-strain on fatigue crack initiation and propagation characteristics. Fatigue test results showed that pre-strained specimens have a shorter fatigue crack propagation life compared to non-strained specimens; this is the opposite of results observed in carbon steel. The accelerated fatigue crack growth observed in pre-strained specimens was first assumed to be caused by precipitate cutting. A dislocation accumulation model for the fatigue crack tip in the precipitation-strengthened material was then suggested. Buff-polished specimens were also used for the fatigue tests, and the results showed that the work-hardened layer had a significant impact on the fatigue strength and fatigue life.
