Deformation behavior and spall fracture of the Hadfield steel under shock-wave loading

Comparative studies of regularities in plastic deformation and fracture of the Hadfield polycrystalline steel upon quasi-static tension, impact failure, and shock-wave loading with rear spall are performed. The SINUS-7 accelerator was used as a shock-wave generator. The electron beam parameters of the accelerator were the following: maximum electron energy was 1. 35 MeV, pulse duration at half-maximum was 45 ns, maximum energy density on a target was 3. 4·10¹⁰ W/cm², shock-wave amplitude was ~20 GPa, and strain rate was ~10⁶ s^-1. It is established that the failure mechanism changes from ductile transgranular to mixed ductile-brittle intergranular one when going from quasi-static tensile and Charpy impact tests to shock-wave loading. It is demonstrated that a reason for the intergranular spallation is the strain localization near the grain boundaries containing a carbide interlayer.