Internal friction and magnetic properties of thermally aged Fe–1wt.% Cu alloys

The purpose of this study is to investigate the internal friction (IF) behaviour of thermally aged Fe–Cu alloys that are model specimens simulating for the irradiation embrittlement of nuclear reactor pressure vessel (RPV) steels. Plate-shaped specimens of Fe–1wt.% Cu alloy were quenched from 1123K and thermally aged at 773K for 103min. The IF of the specimens was measured without magnetic field using the free resonant bending vibration method. Magnetic hysteresis loops and conductivity were also measured. The IF value, hysteresis loss, and conductivity increased under thermal aging, which suggests that the IF characteristics are closely related to the change of electromagnetic eddy-current loss due to the depletion of Cu solute atoms. This study demonstrates the possibility of the application of IF measurement as one of the tools for nondestructive characterization of degradation processes of irradiated RPV steels.