SYMPOSIA PAPER Published: 01 January 2001

Effects of Neutron Irradiation and Thermal Annealing on Model Alloys Using Positron Annihilation Techniques


We present the results of a systematic investigation of neutron-irradiated and thermally annealed Fe-Cu-Ni-P model alloys using positron annihilation spectroscopy (PAS), including lifetime and Doppler broadening techniques, and Rockwell hardness. These alloys were examined in the as-fabricated state, after irradiation at 270° C to 1 × 1019, and to 8 × 1019, and after successive post-irradiation isochronal anneals at temperatures from 200 to 600° C. The results can be qualitatively explained by invoking an irradiation-induced microstructure consisting of a combination of small dislocation-type defects or defect clusters (matrix damage) and dense precipitation of fine scale irradiation-induced precipitates. The matrix damage anneals between 350° C and 450° C. The irradiation-induced precipitates also evolve with annealing, but at higher temperatures. The combined effect of high Cu and high Ni concentrations leads to more extensive irradiation-induced precipitation than in cases where either element is missing, whereas the effect of P is less pronounced. We analyze and compare the results with similar measurements performed on irradiated pressure-vessel steels and with other positron measurements on model alloys, reported in the literature.

Author Information

Cumblidge, ES
The Pennsylvania State University, University Park, PA, USA
Catchen, GL
The Pennsylvania State University, University Park, PA, USA
Motta, AT
The Pennsylvania State University, University Park, PA, USA
Brauer, G
Institut für Ionenstrahlphysik und Materialforschung, Forschungzentrum Rossendorf, Dresden, Germany
Böhmert, J
Institut für Sicherheitsforschung, Forschungzentrum Rossendorf, Dresden, Germany
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Developed by Committee: E10
Pages: 247–261
DOI: 10.1520/STP10537S
ISBN-EB: 978-0-8031-5454-4
ISBN-13: 978-0-8031-2878-1