Modeling the post-yield flow behavior after neutron and electron irradiation of steels and iron-base alloys.

Conference · Wed Jan 13 04:00:00 EST 1999

OSTI ID:11209

Dimelfi, R J

Irradiation hardening is an issue of practical importance as it relates to the remanent life and the nature of failure of reactor components exposed to displacement-producing radiation. For example, irradiation-induced yield strength increases in pressure vessel steels are directly related to increases in the ductile-to-brittle-transition-temperature of these materials. Other issues associated with hardening, such as reductions in ductility, toughness and fatigue life of structural steels are also of concern. Understanding these phenomena requires studies of fundamental microstructural mechanisms of hardening. Because of the limited supply of neutron-irradiated surveillance material, difficulties posed by the radioactivity of neutron-exposed samples and the uncertainty of irradiation conditions in this case, fundamental studies are often conducted using well-controlled experiments involving irradiation by electrons instead of neutrons. Also, in such studies, simple model alloys are used in place of steels to focus on the influence of specific alloy constituents. It is, therefore, important to understand the relationship between the results of this kind of experiment and the effects of in-reactor neutron exposure in order to use them to make predictions of significance to reactor component life. In this paper, we analyze the tensile behavior of pressure vessel steels (A212B and A350) irradiated by neutrons and electrons. The results show that the post-yield true stress/true strain behavior can provide fingerprints of the different hardening effects that result from irradiation by the two particles, which also reflect the influence of alloy content. Microstructurally-based models for irradiation-induced yield strength increases, combined with a model for strain hardening, are used to make predictions of the different effects of irradiation by the two particles on the entire flow curve that agree well with data.

• Research Organization: Argonne National Lab., IL (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 11209
• Report Number(s): ANL/RE/CP-98154
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
ELECTRONS
HARDENING
IRRADIATION
NEUTRONS
PRESSURE VESSELS
REACTOR COMPONENTS
STEELS
STRAIN HARDENING
YIELD STRENGTH