Effect of helium on swelling and microstructural evolution in ion-irradiated V-15Cr-5Ti alloy

Abstract

The effect of helium implantation on the swelling and microstructural evolution in the V-15Cr-5Ti alloy was determined from TEM observations of the alloy after either single-ion irradiation, dual-ion irradiation, or helium implantation followed by single-ion irradiation. In addition to the TEM observations of the irradiated alloy, the effect of helium implantation on the dependence of the RIS of solute atoms was determined by use of the AES, EDXS, and EELS techniques. The swelling of the alloy was negligible (<0.1%) for dual-ion irradiations at temperatures to 725°C and irradiation damage levels to 200 dpa and for single-ion irradiations at temperatures to 750°C and irradiation damage levels to 300 dpa. The morphology and distribution of irradiation-produced precipitates were distinctly different for the single- and dual-ion irradiated alloy. A helium implantation rate in the range of 5 to 9 appm He/dpa caused the accelerated growth of some helium-filled cavities in the alloy to give a bi-modal distribution of cavity sizes.