Magnetoacoustic emission (MAE) and Barkhausen emission (BE) in ferromagnetic materials originate from interactions between moving magnetic domain walls and pinning points such as dislocations and precipitates, giving signatures characteristic of the microstructure. These phenomena have been used to monitor and compare neutron irradiation damage, postirradiation annealing, and thermal aging in annealed or cold-worked α-iron and in iron-copper alloys, selected as simple model systems.

Irradiation at 60°C to 2.9 × 10 19 n / cm 2 ( E > 1 Me V ) suppresses initially strong MAE and BE activity in annealed α-iron, and the trends are consistent with the irradiation-induced dissolution of nitride precipitates. The isochronal annealing characteristics of irradiated, cold-worked α-iron suggest that radiation damage can assist in the thermal recovery of cold-work.

The techniques appear sensitive to the coarsening stages of copper precipitation in a thermally aged iron (Fe)-0.7% copper (Cu) alloy, and to postirradiation recovery in an Fe-0.2% Cu alloy following 290°C-irradiation to 2.4 × 10 19 n / cm 2 ( E > 1 Me V ). The MAE and BE characteristics of the irradiated alloy are consistent with the presence of both a dislocation loop and an irradiation-induced copper precipitate component in the microstructure.

The studies suggest that MAE and BE techniques have the potential to be used in the nondestructive monitoring of neutron-irradiation-induced changes in ferritic alloys.