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内容記述 |
F82H steel is a promising structural material for the blanket system of the fusion DEMO reactor. Given its expected operating temperature range of 573–823 K, it is essential to understand the evolution of irradiation-induced microstructures over a wide temperature range. In this study, specimens of F82H were irradiated with a single iron beam up to 80 dpa at temperatures ranging from 573 to 673 K. A comprehensive analysis was subsequently performed using TEM/STEM observation, including high-resolution STEM-EDS, to examine the stability of fine precipitates and irradiation-induced defects in F82H-IEA steel. The size and type of dislocation loops increased nonlinearly with irradiation temperature, while their number density decreased linearly. These trends were consistent with previous studies. Evaluating the summation area of dislocation loops per unit volume, incorporating reference data, revealed that the area increased with irradiation temperature up to approximately 700 K and decreased rapidly above. This behavior is presumably related to the underestimation of loop size and number density in the conventional TEM/STEM observation due to the growth of the dislocation loop. Regarding the phase stability of the precipitates, amorphization of the M23C6 was observed at temperatures below 623 K, and the irradiation dose was also identified as an important factor. Additionally, high-resolution STEM-EDS analysis revealed a loss of W segregation at the 8c site due to irradiation, which provides direct evidence of chemical/topological disordering. |
