Mechanical Properties at High Strain Rate of AISI Type 316L Stainless Steel Irradiated to 9.2 dpa

The effects of strain rate (10⁻² to ~10⁻³/s) are reported on the mechanical properties at high temperature (400, 500, and 550°C) of AISI Type 316L austenitic stainless steel irradiated to 9.2 displacements per atom (dpa) at a temperature of 500°C in sodium. The main effects are:

1. a softening effect that appears at large deformations and at medium strain rate (~10/s),

2. reduction of ductility when strain rate increases from low (10⁻²/s) to medium strain rate, and

3. disappearance of both these effects at high strain rate (~600/s). The comparison of the mechanical properties of the same material irradiated to 2.2 dpa and 9.2 dpa revealed that while the “static” strength properties were practically unaffected by the increased dose, the dynamic softening at large deformations and the reduction of ductility at medium strain rate were enhanced.