Development of an instrumented indentation device for further characterization of irradiated steels at high temperature

Considering its ability to characterize the tensile behavior of irradiated RAFM steels, the technique of indentation is of particular interest for use at both room- and high temperatures. In the present work, room temperature indentation tests indicate that post-irradiation annealing treatments realized at 500/550 ° C lead to a partial recovery of the embrittlement and strengthening effects observed in samples highly affected by the irradiation temperature of 250 ° C at 15 dpa. Further characterizations of such irradiated steels by indentation at high temperatures are required for a more complete description of the mechanical behavior. To enable such investigations, a new instrumented indentation device has been conceived for testing samples at up to 650 ° C in a high-vacuum atmosphere in a Hot Cell of the Karlsruhe Fusion Materials Laboratory. The final design of the device conceived is presented here. In addition to the constraints of remote handling to be taken into account for operation in a Hot Cell, the design of the test facility notably results from the development of an adapted heating system. Moreover, a digital image processing-based technique was selected according to its ability to measure indentation depths at sub-micrometer resolutions. The corresponding optical setup was defined for the adaptation to the testing device.