Effect of irradiation temperature on the nanoindentation behavior of P92 steel with thermomechanical treatment

The nanoindentation behavior of P92 steel with thermomechanical treatment under 3.5 MeV Fe13+ ion irradiation at room temperature, 400 and 700 °C was investigated. Pop-in behavior is observed for all the samples with and without irradiation at room temperature, while the temperature dependence of pop-in behavior is only observed in irradiated samples. The average load and penetration depth at the onset of pop-in increase as the irradiation temperature increases, in line with the results of the maximum shear stress. Irradiation induced hardening is exhibited for all irradiated samples, but there is a significant reduction in the hardness of sample irradiated at 700 °C in comparison to the samples irradiated at room temperature and 400 °C. The ratio of hardness to elastic modulus for all samples decreases with increasing penetration depth except for samples at 700 °C. With the increasing of irradiation temperature, the ratio of the irreversible work to the total work gradually decreases. In contrast, it increases for samples without irradiation.