Study of the effect of helium, irradiation, and temperature on the embrittlement of Inconel X-750 CANDU garter spring spacers

该项目将使用高能离子辐照，结合微观机械测试和微观结构分析，评估辐照损伤、辐照温度和氦积累对Inconel X-750 CANDU吊袜弹簧垫片的强度、塑性和晶界脆化倾向的影响。在Inconel X-750样品中，将在两个温度下注入不同数量的氦离子，然后注入高能镍离子，以引起类似于中子辐射所造成的晶体损伤。将使用纳米压痕硬度测试来评估累积的氦和离子辐照损伤对Inconel合金硬度的综合影响。聚焦离子束球磨将被用来制造长约100微米的悬臂梁，横跨离子注入样品的选定晶界。然后对这些梁进行弯曲测试，以评估氦和辐射损伤对晶界强度的影响。 该项目将首次提供实验证据，将中子辐照损伤和氦积累与Inconel X-750CANDU吊袜弹簧垫片的硬化和晶界脆化联系起来。这些数据目前非常重要，因为它们影响到目前在CANDU反应堆中服役的燃料通道部件是否适合使用。

This proposed project will use high energy ion irradiation combined with micro-mechanical testing and micro-structural analyses to assess the effect of irradiation damage, irradiation temperature, and helium accumulation on the strength, ductility, and tendency for grain-boundary embrittlement of Inconel X-750 CANDU garter spring spacers. Various amounts of helium ions will be implanted, at two temperatures, into Inconel X-750 samples followed by implantation of high energy nickel ions to invoke crystallographic damage similar to that resulting from neutron irradiation. Nano-indentation hardness testing will be used to assess the combined effect of the accumulated helium and ion-irradiation damage on the hardness of the Inconel alloy. Focused ion beam milling will be used to fabricate cantilever micro-beams, about 100 micrometers in length, across selected grain boundaries of the ion-implanted samples. These beams will then be tested by bending to assess the effect of the helium and irradiation damage on the strength of the grain boundaries. This project will present, for the first time, experimental evidence linking neutron irradiation damage and helium accumulation to the hardening and the onset of grain boundary embrittlement in Inconel X-750CANDU garter spring spacers. These data are currently of great importance since they impact the determination of fitness for service of fuel channel components that are currently in service in CANDU reactors.