Segregation Effects in Ferritic Fe-Cr Alloys

A series of alloys based on Fe-10Cr with solute additions of silicon, vanadium, manganese, tungsten, tantalum, and zirconium at 0.1 and 1.0% levels, has been examined by transmission electron microscopy following fast neutron irradiation. Marked differences in dislocation evolution and void shape following neutron irradiation were found as a function of alloying. The present study extends previous examinations by investigating microstructural response following irradiation at a lower temperature (365°C) to 30 dpa and to a higher dose, 100 dpa, at 410°C. Swelling level, void shape, and dislocation configuration continued to vary as a function of the various solutes present in the same manner as seen previously. However, two additional observations were made. Irradiation at the lower temperature promotes precipitation of chromium rich α phase and reduces microstructural evolution. Also, irradiation to higher dose, reduces the effect each solute exerts by lessening the wide variation in void shape and dislocation evolution that were found at lower dose.