Effect of shock waves on microstructure and fracture behavior of pre-cracked steel weld metal

Pre-cracked C–Mn Steel weld metal specimens were shock-treated (with a peak pressure of 5 GPa). The fracture behavior of the shock-treated specimens and the microstructure around the pre-crack tip were investigated. The results show that the shock-treated specimens have significantly increased fracture resistance ability at various test temperatures. A softening fine grain zone was found around the pre-crack tip. It was believed that the softening fine grain zone was formed during the adiabatic shearing process when shock waves pass through the specimen. The zone around the pre-crack tip is suggested to play an important role in influencing the fracture behavior of the shock-treated specimen.