Elevated Temperature Irradiation Effects Research On P92 Steel

Due to its well thermal conductivity, good dimensional stability, excellent high temperature(400-550°C) anti-radiation ability, very good resistance to irradiation swelling and brittleness, anti-irradiation-induced creep, etc., the 9-12% Cr ferritic / martensitic steels has an essential role in applied research in the fourth generation of advanced reactors. In this study, self-ion(Fe13+) beams were irradiated to P92 steel at 700°C,and TEM observation and nano-indentation measurements were performed,the microstructure stability evaluation of high temperature ferritic / martensitic steel exposure to self-ion(Fe13+) beams were drawn.Note that no distinct structural change was observed even after ion irradiation?The voids appeared in the surface were found in the P92 ferritic / martensitic steels after ion irradiation. With increasing irradiation temperature irradiation, the more swelling empty were formation. The Cr-rich M23C6 and Nb-rich, Ta-rich phase of MX were characterized. The precipitates decreased in the irradiation peak region(800-1200nm) relative to the irradiation surface area(0-400nm) in P92 ferritic /martensitic steels after irradiation, indicates that the precipitates in the in the irradiation peak region(800-1200nm) dissolved in the matrix,and the precipitate would re-precipitation a small amount. Resulting to the number density of the precipitates reduced in the irradiation peak temperature region(800-1200nm). The non-equilibrium segregation occurred in the matrix/carbide interface after irradiation, the concentration of Cr and W in carbides would increased while the concentration of Fe depletion. Two types of dislocation loops of <100> and 1/2<111> under different condition of diffraction were discussed. The average size increased after irradiation, while the number density of the dislocation defects showed visual reduction. The dislocation defects evolved into dislocaton tangles, dislocation walls and sub-boundaries by accumulation and rearrangement under the influence of irradiation, this conclusion analysis agreed well with the transformation of dislocation defects.After ion irradiation to 0.75 dpa and 3.77 dpa, the hardness decreased 0.5, 0.7 GPa from an initial value of 4.5 GPa before irradiation, respectively. The hardness irradiated to 0.75 dpa was slightly higher than that to 3.77 dpa in 700°C. The results indicated the irradiation may alleviate the hardness of the samples. Such irradiation softening behavior were interpret by the evolution of the microstructure.