Magnetic After-Effect Study of the Cu-Precipitation in Thermally Aged Fe-1%Cu Alloys

A magnetic after-effect setup is developed and used to study the Cu-precipitation process in thermally aged Fe-1%Cu alloys, as a complementary process to the irradiation-induced hardening due to Cu-precipitation in iron-based alloys used as structural materials in the nuclear industry. The magnetic relaxation spectra, measured in the temperature region from 200 K to 500 K, show the existence of two relaxation processes centered at 260 K and 330 K, which are assigned as the Snoek-carbon relaxation process and thermal activation of dislocation motion, respectively. The copper precipitation is found to influence the carbon migration as well as the dislocation pinning.