Microstructure change and helium release due to tensile loading on austenitic stainless steel implanted with low energy helium ions

Abstract

Microstructure change and helium release due to tensile loading on 304SS specimens implanted with low energy helium ions have been investigated. Specimens are irradiated with 8 keV helium ions at RT, 573 K and 873 K up to the fluence of 3 × 10 21 He/m 2. Tensile tests are performed at RT on unirradiated and irradiated specimens at a strain rate of 3.33 × 10 −3/s. In every irradiation condition, specimens were tested to failure, and were elastically strained, yield point and plastically strained to 10%, 20% and 40% (total strain). After the tensile test, surface modification and microstructure change are observed with a scanning electron microscope (SEM) and a transmission electron microscope (TEM), respectively. It is shown that surface morphology and microstructure of irradiated specimens after the tensile test are drastically different from that of unirradiated specimens. The tensile loading also influences behavior of thermal desorption of helium and trap sites.