THE EFFECT OF HYDROGEN ON MICROSTRUCTURAL CHANGES USING DUAL-ION IRRADIATION

The effect of hydrogen on cavity formation in vanadium was investigate d using dual ion irradiation at 773,873 and 973 K with hydrogen inject ion of 0, 15, 30 and 60 appm/dpa for doses up to 50 dpa. In some of th e samples after dual beam irradiation with H and Ni ions, bimodal cavi ty size distribution was observed. The injected hydrogen may affect ca vity nucleation in a similar manner as helium. There is a critical rad ius of the cavity under H dual irradiation which depends on the irradi ation temperature, like He dual irradiation. The dependence of the cri tical radius on the amount of injected hydrogen is not clear, but it i s suggested that the amount of hydrogen more than a certain value is n ecessary to promote the nucleation of cavities by injected hydrogen.