Mechanical properties of tungsten irradiated with high-energy protons and spallation neutrons

In this work, 3-point bending tests and micro-hardness measurements were performed on pure tungsten irradiated with high-energy protons and spallation neutrons in a target of the Swiss Spallation Neutron Source (SINQ). The specimens were irradiated to doses in the range of 1.3–3.5 dpa, with 37–140 appm He, at temperatures between 75 and 110 °C. During 3-point bending tests performed at temperatures up to 500 °C, all the irradiated specimens fractured in the elastic regime at stresses much below those for the unirradiated reference specimens. The micro-hardness measurements indicate significant irradiation induced hardening under all irradiation conditions. Observation of the fracture surfaces of tested irradiated specimens shows brittle fracture behaviour in general, whereas detailed features depend strongly on irradiation dose and test temperature.