VOID FORMATION AND PRECIPITATION IN NEUTRON-IRRADIATED VANADIUM ALLOYS

In order to investigate the effect of alloying elements on void formation and precipitation during neutron irradiation, V and V based alloys were irradiated in the experimental fast breeder reactor 'JOYO' up to 1×1025 n/m2 at 670-870 K. Voids were formed in almost all of the samples, with the exception of the V-C and V-Ti alloys. Precipitation was not observed in the V-Mo alloy, and homogeneous void formation occurred, where although the resultant swelling was not large. On the contrary, V-Cr alloy exhibited inhomogeneous void formation, and the swelling was larger than in V. Observations indicated that the void formation was related to the radiation-induced precipitates which nucleated on pre-existed dislocations. The void formation and precipitation behavoir are discussed terms of the effect of alloying. ?