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.本研究采用激光冲击喷丸（laser shock peening，LSP）与等离子冲击喷丸（plasma shock peening，PSP）工艺对304不锈钢试样进行处理。随后通过多种非破坏性检测手段对上述试样开展表征分析，研究重点聚焦试样表面特性。借助扫描电子显微镜（scanning electron microscopy，SEM）对未处理及抛光后的试样表面进行成像，结果显示经LSP与PSP处理后，试样表面形貌均呈现出一定程度的定向排列特征。能量色散X射线光谱（energy dispersive X-ray spectroscopy，EDS）分析表明，在约2 μm厚的表层内，合金元素的分布未发生显著变化。X射线衍射（X-ray diffraction，XRD）检测发现，原始试样与经处理后的试样均以奥氏体（面心立方，FCC）相为主要组成相；铁素体（体心立方，BCC）相为次要组成相，占比约4%~8%。同时，经LSP与PSP处理后，铁素体相含量似乎略有提升，但该变化处于测量不确定度的极限范围内。不过，采用CXMS的穆斯堡尔谱检测未在约30 μm厚的表层中检出铁素体相；而采用CEMS的穆斯堡尔谱检测则可检出铁素体相，但该结果仅表明其存在于0.3 μm厚的表层内。该铁素体相大概率源于原始试样的初次切割工序，且LSP与PSP处理并未引起试样相组成发生明显改变。本研究采用的另一项实验表征手段为正电子-电子湮没技术，其中湮没线多普勒展宽（Doppler broadening of the annihilation line，DBS）方法检测结果显示，经LSP与PSP处理后，试样的原子级缺陷浓度略有提升。通过正电子湮没寿命谱（positron annihilation lifetime spectroscopy，PALS）测得的所有试样的正电子寿命，均长于经700 ℃退火处理的相对无缺陷试样的正电子寿命；但无法明确区分原始试样与经LSP、PSP处理试样之间的正电子寿命差异。