RAFM steels EUROFER97 and EU-ODS EUROFER samples have been implanted with He ions at 40 keV (ion penetration depth ~300 nm) at a dose of ~ 1 × 10¹⁵ ion/cm² and different temperatures up to 550 °C.

Post-irradiation examination of the samples has been performed using nanoindentation along with conventional and scanning transmission electron microscopy (CTEM/STEM in Annular Dark Field mode). The specimens were indented up to 500 nm by CSM method (Continuous Stiffness Measurement), in order to assess the changes in nanoindentation hardness values due to the irradiation. After indentation tests, lamella was extracted from each implanted sample which included at least one nanoindentation cross-section. The changes in hardness were correlated with any microstructure modification detected by TEM. A clear trend can be observed; the hardness values increased with irradiation temperature, as well as the He bubble nucleation and population density. A remarkable change in bubble distribution in EUROFER97 was found at the two highest irradiation temperatures (450 °C and 550 °C). In contrast, an increase in the cavities size was observed in EU-ODS EUROFER, but no new nucleation was observed for the same temperatures. These observations suggest that for these particular conditions, the cavity growth is enhanced, rather than new nucleation, which depends strongly on the material microstructure.

RAFM钢EUROFER97和EU-ODS EUROFER样品已植入40 keV（离子穿透深度〜300 nm）的He离子，剂量约为1×10 ¹⁵ ion / cm ^2，并且在高达550°C的不同温度下进行了注入。

样品的辐照后检查已使用纳米压痕以及常规和扫描透射电子显微镜（环形暗场模式下的CTEM / STEM）进行。通过CSM方法（连续刚度测量）将样品压痕至500nm，以便评估由于照射导致的纳米压痕硬度值的变化。压痕测试后，从每个植入的样品中提取薄片，其中至少包括一个纳米压痕横截面。硬度的变化与通过TEM检测到的任何微观结构改变相关。可以观察到明显的趋势；硬度值随辐照温度，氦泡成核度和密度的增加而增加。在两个最高辐照温度（450°C和550°C）下，EUROFER97中的气泡分布发生了显着变化。相反，在EU-ODS EUROFER中观察到腔体尺寸增加，但在相同温度下未观察到新的成核现象。这些观察结果表明，对于这些特定条件，空腔的生长得到增强，而不是新的成核，而新的成核在很大程度上取决于材料的微观结构。