Changes in the magnetic and mechanical properties of thermally aged Fe–Cu alloys due to nano-sized precipitates

Abstract

The changes in the magnetic properties, mechanical properties, and microstructural parameters of Fe–Cu alloys due to thermal aging have been investigated to improve the fundamental understanding of using magnetic technology for the nondestructive evaluation (NDE) of irradiation embrittlement in the reactor pressure vessel (RPV). Nano-sized Cu particles precipitated from a Fe matrix after thermal aging at 500 °C for various times, and the microstructure parameters were determined. The coercivity, Barkhausen noise (BN), Vickers hardness, and yield stress were also measured for these samples. These properties show the same hardening–softening trend with increasing aging time, which can be interpreted in terms of the microstructure parameters evolution based on the model of the pinning of precipitates on domain walls and dislocations. These results suggest the practicability of using magnetic technology for the NDE of the irradiation embrittlement of the RPV.