skip to main content


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

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 °C, and to 1, 10 and 20 dpa at 600 nm depth at 470 °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 °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 α' phase, χ-phases, η 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 increasedmore » whereas the number density decreased with increasing irradiation temperature. Within the same irradiation temperature, the average size increased with increasing irradiation dose.« less
ORCiD logo [1] ;  [2] ;  [2] ;  [1]
  1. North Carolina State Univ., Raleigh, NC (United States)
  2. Univ. of Oxford (United Kingdom)
Publication Date:
Grant/Contract Number:
Published Article
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 491; Journal Issue: C; Journal ID: ISSN 0022-3115
Research Org:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE; F/M steel, HT9, Ion irradiation, Radiation-induced segregation & precipitation, G-phase, ChemiSTEM, APT
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1426234