Impact toughness of 12Cr1MoV steel. Part 2 – Influence of high intensity ion beam irradiation on energy and deformation parameters and mechanisms of fracture

• Effects of high intensity ion beam irradiation on impact fracture of steel were investigated.
• The physical regularities of irradiation effect is analyzed for 12Cr1MoV steel.
• Reduction of fracture ductility for modified specimens was established and justified.

The impact toughness of initial and irradiated 12Cr1MoV steel Charpy specimens has been studied in the range of temperatures from 20 °C to 600 °C. In addition, it was found that ion beam treatment of steel deteriorates the impact toughness at the tested temperatures by 5–42%. Moreover, it was revealed that the increase of testing temperature decreases the difference between the fracture energies of initial and modified steel specimens. Also, the physical regularities of irradiation effect on microhardness and hardness of the treated surface were investigated. It was also revealed that irradiated specimens fracture via more brittle mechanism, which is related to both more severe stress–strain state at the notch tip and gradient alteration of properties in the subsurface layer.