Abstract
The potential of ultrasonic surface mechanical attrition treatment (SMAT) at different temperatures (including cryogenic) for improving the fatigue performance of 304L austenitic stainless steel is evaluated along with the effect of the fatigue loading conditions. Processing parameters such as the vibration amplitude, the size, and the material of the shot medias were fixed. Treatments of 20 min at room temperature and cryogenic temperature were compared to the untreated material by performing rotating–bending fatigue tests at 10 Hz. The fatigue limit was increased by approximately 30% for both peening temperatures. Meanwhile, samples treated for 60 min at room temperature were compared to the initial state in uniaxial fatigue tests performed at R = −1 (fully reversed tension–compression) at 10 Hz, and the fatigue limit enhancement was approximately 20%. In addition, the temperature measurements done during the tests revealed a negligible self-heating (∆t < 50 °C) of the run-out specimens, whereas, at high stress amplitudes, temperature changes as high as 300 °C were measured. SMAT was able to increase the stress range for which no significant local self-heating was reported on the surface.
Highlights
In the high cycle fatigue regime, cracks mostly nucleate at the surface of the loaded workpiece.the surface or near-surface features such as surface roughness and residual stresses affect the fatigue life of a component
The presence of surface irregularities leads to high local stresses, which may create a high amount of plastic deformation locally, eventually contributing to crack-type defect creation depending on the intrinsic behavior of the studied material
These grooves were completely removed after min of samples (Figure 1a). These grooves were completely removed after 20 min of surface mechanical attrition treatment (SMAT) at room temperature (RT) (Figure 1b) but not not completely completely for but for the the cryogenic cryogenic treatment treatment(Figure (Figure1c)
Summary
In the high cycle fatigue regime, cracks mostly nucleate at the surface of the loaded workpiece. The surface or near-surface features such as surface roughness and residual stresses affect the fatigue life of a component. The surface roughness has an influence essentially at the crack initiation stage [1]. The presence of surface irregularities leads to high local stresses, which may create a high amount of plastic deformation locally, eventually contributing to crack-type defect creation depending on the intrinsic behavior of the studied material. The presence of residual stresses may affect the crack propagation behavior [2]. While a tensile stress loading promotes crack opening and faster propagation, the introduction of compressive residual stresses can delay or stop
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
