The dose dependence of void swelling in 18/8/Ti stainless steel irradiated with 20 MeV C++ions at 600°C

Abstract

Fast neutron induced voidage has been simulated in solution treated and in 20% cold worked 18/8/Ti stainless steel using 20 MeV C⁺⁺ irradiations in the Harwell Variable Energy Cyclotron. Foils containing 10⁻⁵ helium atoms per atom have been irradiated at 600°C to 5, 10, 20, 40, 60 and 120 displacements per atom. The void swelling at each dose was determined from the volume of the voids observed by transmission electron microscopy. In solution treated steel the void swelling was approximately proportional to dose over a large part of the dose range studied; in 20% cold-worked steel the swelling was proportional to (dose)² in the same dose range. In both cases there was evidence of saturation at doses ⩾ 60 d.p.a. The void swelling was lower in 20% cold-worked than in solution-treated steel at all doses, but the difference, diminished with increasing dose.