This paper describes the results of an investigation of the influence of neutron irradiation on mechanical properties of a low-alloy structural weldable steel under impulsive loading produced by means of the Hopkinson split pressure bar (HSPB) method. The general analysis of the HSPB technique is outlined briefly and applications to the irradiated steel are considered in greater detail.

The investigated steel was irradiated by fast neutrons to an exposure of 3.5 × 10²⁴ neutrons (n) m⁻². Extensive dynamic measurements provided the dependence of the flow stress σ_fi on strain rate ge in the interval 10²–10³s⁻¹.

Particular attention is paid to the influence of postirradiation annealing on the material's recovery. Experiments performed at various annealing temperatures (200 to 400°C) and annealing times (16 to 168 h) are analyzed. The results show that the neutron irradiation does not influence the mechanisms of plastic flow at high rates of strain. Our original interpretation of the HSPB approach makes it possible to determine the plastic wave speed at different levels of recovery.