On the Influence of Ultrasonic Surface Mechanical Attrition Treatment (SMAT) on the Fatigue Behavior of the 304L Austenitic Stainless Steel

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.

Severe Plastic Deformation and Thermomechanical Processing: Nanostructuring and Properties

“…Thirteen research papers have been published in this Special Issue of Metals. The papers cover a wide spectrum of topics, including (i) deformation mechanisms, the mechanical properties and fatigue behaviour of SPD-processed materials [1][2][3][4][5][6][7], (ii) microstructural and mechanical stability at elevated temperatures [8,9], phase formations in alloys [10], the improvement of physical properties (electrical conductivity [11], magneto-resistance [12]) and biomedical properties (biocorrosion resistance [6], biocompatibility [13]) by SPD.…”

“…The influence of texture and microstructure on the mechanical properties and deformation mechanisms was thoroughly studied and a compressive yield strength more than twice as high as that of the undeformed alloy was reached. Dureau et al [4] investigated the influence of ultrasonic SMAT treatment at room and cryogenic temperatures on the fatigue behaviour of a 304L austenitic stainless steel with a focus on the nature of the cyclic loading conditions. In the case of this steel, the higher fraction of martensite induced by the cryogenic SMAT did not provide an enhancement of fatigue performance compared with the room temperature treatment.…”

Evaluating the Homogeneity of Surface Features Induced by Impact-Based Surface Treatments

“…Despite the exhaustive list of surface texture parameters suggested by these standards, the majority of the studies, particularly in the field of impact-based surface treatments, refer to the single parameter of the arithmetical mean deviation (Ra/Sa) [6][7][8] or root mean square deviation (Rq/Sq) [9] of the assessed profile/surface as the only index to describe surface roughness. These most commonly used parameters are occasionally accompanied by Rt/St or Rz/Sz [10][11][12] that are all local parameters directly related to the distance between the highest peaks and the lowest valleys in the measured profile/area.…”

Surface Properties and Corrosion Behavior of Turn-Assisted Deep-Cold-Rolled AISI 4140 Steel

“…Therefore, improving the surface properties of machine components that work under fatigue and corrosion is an effective way to enhance the service life of the components. Although surface alteration by application of the deep-cold-rolling process is quite new, it has received substantial demand due to enhanced residual compressive stress (Ref 29,45) , surface work hardening (Ref 28,46) , surface finish (Ref 18,47) and grain refinement which in turn will have the positive effect on corrosion properties. Therefore, a surface enhancement method improving the surface properties after the machining would be beneficial along with the effective use of the design of experiment to reduce the time and number of experiments to be conducted.…”

“…Therefore, a surface enhancement method improving the surface properties after the machining would be beneficial along with the effective use of the design of experiment to reduce the time and number of experiments to be conducted. Based on the above literature analysis, it is clear that the effects of deep-cold-rolling process parameters on the surface integrity of titanium alloys, magnesium alloys, and hardened steel have been explored (Ref 4,23,28,34,45,48,49). However, the literature on the effects of various deep rolling parameters on the surface integrity of AISI 4140 steel is limited (Ref 49,50).…”