Radiation induced segregation and precipitation behavior in self-ion irradiated Ferritic/Martensitic HT9 steel

JOURNAL OF NUCLEAR MATERIALS

卷:491

Article

Zheng, Ce¹  Auger, Maria A.²  Moody, Michael P.²  Kaoumi, Djamel¹ 

[1] North Carolina State Univ, Dept Nucl Engn, Raleigh, NC 27607 USA

[2] Univ Oxford, Dept Mat, Parks Rd, Oxford OX1 3PH, England

关键词: F/M steel;    HT9;    Ion irradiation;    Radiation-induced segregation & precipitation;    G-phase;    ChemiSTEM;    APT;   

DOI  :  10.1016/j.jnucmat.2017.04.040

来源: Elsevier

【 摘 要 】

In this study, Ferritic/Martensitic (F/M) HT9 steel was irradiated to 20 displacements per atom (dpa) at 600 nm depth at 420 and 440 degrees C, and to 1, 10 and 20 dpa at 600 nm depth at 470 degrees C using 5 MeV Fe++ ions. The characterization was conducted using ChemiSTEM and Atom Probe Tomography (APT), with a focus on radiation induced segregation and precipitation. Ni and/or Si segregation at defect sinks (grain boundaries, dislocation lines, carbide/matrix interfaces) together with Ni, Si, Mn rich G-phase precipitation were observed in self-ion irradiated HT9 except in very low dose case (1 dpa at 470 degrees C). Some G-phase precipitates were found to nucleate heterogeneously at defect sinks where Ni and/or Si segregated. In contrast to what was previously reported in the literature for neutron irradiated HT9, no Cr-rich alpha' phase, x-phases, eta phase and voids were found in self-ion irradiated HT9. The difference of observed microstructures is probably due to the difference of irradiation dose rate between ion irradiation and neutron irradiation. In addition, the average size and number density of G-phase precipitates were found to be sensitive to both irradiation temperature and dose. With the same irradiation dose, the average size of G-phase increased whereas the number density decreased with increasing irradiation temperature. Within the same irradiation temperature, the average size increased with increasing irradiation dose. (C) 2017 The Authors. Published by Elsevier B.V.

【 授权许可】

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