Effects of heat treatment and irradiation on mechanical properties in F82H steel doped with boron and nitrogen

Effects of heat treatment and irradiation on mechanical properties and microstructures have been studied for martensitic steel F82H co-doped with 60 ppm B and 200 ppm N (F82H + B + N) to evaluate fundamental mechanical properties and irradiation response before irradiation at JMTR and HFIR facilities. The specimens were firstly normalized at 1150 °C and tempered at 700 °C, secondly normalized at 1000 °C and tempered at 700, 750 and 780 °C. The tensile properties were measured for the specimens before irradiation. Single ion irradiations of 10.5 MeV Fe3+ and dual ion irradiations of 10.5 MeV Fe3+ with simultaneous 1.05 MeV He+ of 10 appmHe/dpa rate were performed at 160–590 °C to 20 dpa. Micro-hardness was measured before and after the irradiation. Tensile properties of the F82H + B + N were similar to F82H and also radiation hardening behaved similarly to F82H. The change of hardening increased with increasing temperature, saturated around 350 °C and decreased at higher temperature.