Key factors in radiation tolerance of BCC metals under steady state.

Different materials would exhibit discrepant behaviors of radiation tolerance under energetic particle irradiation, due to the effect of intrinsic features (like defect migration energy and sink strength of grain boundaries) and extrinsic conditions (like irradiation rate and temperature) on defect accumulation. We wonder what the general rules of radiation tolerance are in body-centered cube (BCC) transition metals. Based on the steady state chemical rate theory, the influence of these intrinsic features and extrinsic conditions on vacancy accumulation is thus investigated in typical BCC metals including V, Cr, Fe, Nb, Mo, Ta and W. It shows that V, Cr, Fe and Nb exhibit obvious advantage in radiation resistance than that of Ta, Mo and W under typical service conditions, due to their higher vacancy diffusivities. In addition, the smaller grain size and lower irradiation rate, the higher anti-irradiation ability of BCC metals. Therefore, we propose that, under practical irradiation rates and temperatures, BCC metals with low vacancy migration energy and small grain size should be recommended in the selection of new nuclear materials, at least in the view of steady state. [ABSTRACT FROM AUTHOR]