高He通量注入条件下F/M和ODS钢中纳米微结构对He泡形核和长大的影响

利用LEAF装置提供的2 MeV的He离子，在500和600 °C分别对新型F/M钢-SIMP钢和ODS钢(MA956和Eurofer-ODS钢)注入1×1017 ions/cm2的高通量He离子，借助透射电子显微镜，表征了辐照后三种材料的肿胀行为，验证了各材料中纳米微结构(晶界，析出相和纳米氧化物)对辐照后He泡成核和长大的影响。结果表明，基于材料中晶界和析出相对He泡生长的抑制作用，温度为500 °C时，SIMP和Eurofer-ODS钢表现出较高的抗辐照肿胀性能，而MA956中纳米界面He泡成核和长大作用不明显，表现出较差的抗辐照肿胀性能；此外，温度为600 °C时，Eurofer-ODS钢由于其晶界和氧化物界面的较强作用，表现出较好的抗辐照肿胀性能。总体来说，在高He通量注入条件下，材料中纳米结构的存在会抑制He泡长大的过程，但不同材料中纳米结构对He影响作用不同。

Effect of Nanostructures on Bubbles Nucleation and Growth in F/M and ODS Steels Exposed with High Helium Fluence

A new type of F/M steel (SIMP steel) and two kinds of ODS steels (MA956 and Eurofer-ODS steels) were irradiated by 2 MeV He ions to fluence of 1×1017 ions/cm2 at 500 and 600 °C. After irradiation, swelling behaviors and effect of nanostructures (such as grain boundaries, precipitates and nano-oxide particles) on the nucleation and growth of He bubbles were studied by transmission electron microscope. The results show that both SIMP and Eurofer-ODS steels exhibit better swelling resistance than MA956 ODS steel at 500 °C, because the grain boundaries or precipitates pronouncedly inhibit the growth of He bubbles. The Eurofer-ODS steel shows best swelling resistance due to the inhibition of He bubbles growth by the grain boundary and oxide interface at 600 °C. The present work shows that nanostructures in materials inhibit the process of He bubble growth under high He fluence conditions, but the degree of inhibition varies with different materials.