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与传统的铁素体钢相比,氧化物弥散强化(ODS)的铁素体钢具有更优的耐高温和抗辐照性能,近年来成为先进核能装置重要的候选结构材料。在HIRFL的扇聚焦型回旋加速器(SFC)材料辐照终端,对一种氧化物弥散强化(ODS)铁素体钢MA956进行了高能Ne离子辐照实验,旨在研究级联碰撞损伤和惰性气体原子注入条件下该材料力学性能的变化。利用辐照终端的能量衰减装置将SFC出口123.4 Me V的离子能量分解为介于38.5～121.0 Me V之间的30个入射能量值,并通过双面辐照在厚度60μm的样品中均匀产生了损伤。辐照剂量为9×1016ions/cm2,在样品中的平均位移损伤为0.7 dpa,注入的Ne原子浓度为350 appm。辐照期间样品温度保持在440℃附近。对辐照前后的样品分别在室温和500℃下进行了小冲杆试验(Small-punch Test),获得了辐照前后样品的加载位移曲线,由此得到该辐照条件下样品的延性损失为18%～26%。通过扫描电子显微镜观察了断口形貌和厚度变化,估算了样品的等效断裂应变和断裂韧性。结果表明,MA956钢经过高能Ne离子辐照后等延伸率减小,断裂韧性降低,样品发生了一定的脆化。透射电镜结果说明氧化物弥散相界面处微空洞的形成可能是导致脆化的原因。
Compared with traditional ferritic steels, ODS ferritic steels have better heat resistance and radiation resistance and have become important candidate structural materials for advanced nuclear power plants in recent years. At HIRFL’s fan-focused cyclotron (SFC) material irradiation end, a high energy Ne ion irradiation experiment was performed on an oxide dispersion strengthened (ODS) ferritic steel, MA956, to study cascading collision damage and inert gas Mechanical properties of the material under atomic injection conditions. The ion energy of 123.4 MeV at the SFC outlet was decomposed into 30 incident energy values between 38.5 and 121.0 MeV using the energy attenuator at the irradiation terminal and uniformly generated in a sample of 60 μm thickness by double-sided irradiation damage. The irradiation dose was 9 × 1016ions / cm2. The average displacement in the sample was 0.7 dpa. The injected Ne atom concentration was 350 appm. The sample temperature was maintained around 440 ° C during irradiation. The small-punch test was carried out on the samples before and after irradiation at room temperature and 500 ℃, respectively, and the loading and displacement curves of the samples before and after irradiation were obtained. The ductility loss of the samples under the irradiation conditions was 18% ~ 26%. The morphology and thickness of the fracture were observed by scanning electron microscopy. The equivalent fracture strain and fracture toughness of the sample were estimated. The results show that the elongation of MA956 steel decreases after irradiation of high energy Ne ions, the fracture toughness decreases, and the sample has some embrittlement. Transmission electron microscopy showed that the formation of micro-cavities at the oxide-dispersed phase interface may be the cause of embrittlement.