Clustering and precipitation in neutron irradiated low copper and copper-free steels and model alloys

The role of copper in the embrittlement of A533B and related steels used as the pressure vessels of nuclear reactors has been the subject of numerous atom probe investigations. As copper is deleterious to the mechanical properties of these neutron irradiated steels, some copper-free and low copper alloys have been investigated with the local electrode atom probe to ascertain if any other types of precipitates or clusters form with the other alloying elements. These model alloys were specifically designed to search for radiation enhanced precipitation of various phases (phosphides, silicides and manganese-nickel precipitates) in copper-free and low copper alloys.