VOID FORMATION AND MICROSTRUCTURAL DEVELOPMENT IN OXIDE DISPERSION-STRENGTHENED FERRITIC STEELS DURING ELECTRON-IRRADIATION

ODS ferritic steels (13Cr-0.5Ti-0.2Y(2)O(3)) were prepared by the mech anical alloying method followed by the hot extrusion and several heat treatments including recrystallization. ODS steels with different heat treatment and a ferritic/martensitic (F/M) steel for the reference we re irradiated to 12 dpa at 670-770 K in HVEM. After recrystallization, the dislocation density decreased with increasing grain size, however , the oxide particles did not show any obvious change in the size and the number density. During the electron-irradiation the microstructure was relatively stable, i.e. oxide particles showed good stability and the dislocation density remained almost constant. A limited void form ation was observed in the specimens, and the suppressive effect due to dislocations with high number density was confirmed. From these resul ts, the behavior of microstructure and the limited void formation in O DS steels have been discussed. (C) 1998 Published by Elsevier Science B.V. All rights reserved.