Study of 304 steel after LSP and PSP processing (dataset).

Samples of 304 stainless steel were treated using the LSP (laser shock peening) and PSP (plasma shock peening) methods. These samples were then studied using a range of non-destructive methods, focused primarily on studying the surface of the samples. The surfaces of unprocessed and polished samples were imaged using scanning electron microscopy (SEM). SEM images showed a certain degree of surface morphology alignment after both LSP and PSP processing. Energy dispersive X-ray spectroscopy (EDS) showed that there was no change in the distribution of alloying elements in the surface layer of approximately 2 μm. X-ray diffraction (XRD) identified a dominant austenitic (FCC) phase in both the original and processed samples. A ferritic (BCC) phase was identified as a minor phase (4-8%). At the same time, it appears that both LSP and PSP processing slightly increases the ferritic phase content. However, this is at the limit of measurement uncertainty. However, Mössbauer spectroscopy using CXMS did not identify a ferritic phase in the surface layer of approximately 30 μm. The ferritic phase was identified using CEMS, but this only indicates its presence in the surface layer of 0.3 μm. This phase probably originated during the primary cutting of the initial samples. No changes in phase composition occurred as a result of LSP and PSP processing. Another experimental method used was positron-electron annihilation. The Doppler broadening of the annihilation line (DBS) method showed that, as a result of both LSP and PSP processing, there was a slight increase in the concentration of defects at the atomic level. The positron lifetimes determined using PALS are longer in all samples than in the sample annealed at 700 °C (a relatively defect-free sample). At the same time, it is not possible to clearly demonstrate a difference in positron lifetimes in the initial and LSP and PSP machined samples.