At the Australian Nuclear Science Technology Organisation (ANSTO), the Nuclear Materials and Development Characterisation (NMDC) platform facilitate research led by Nuclear Fuel Cycle (NFC) research team. Research led by NFC focuses on (1) materials which could be used in generation IV nuclear reactors; (2) absorbent materials for capturing and storing nuclear waste; (3) materials which have been irradiated. This presentation will provide a snapshot of the microscopy performed on nuclear related materials with NMDC equipment at ANSTO.
The following describes once case study, which will be included in this presentation. The strain rate sensitivity of Ni single crystal samples pre and post helium ion irradiation were investigated via in-situ micro-tensile testing. Ni single crystals were exposed to ion fluence of 4.4x1017 ions/cm2 at room temperature using 5 MeV He+ ions. A degrader wheel was used during irradiation to attenuate the energy and ensure a more uniform distribution of damage throughout its depth. Micro-tensile samples of 10 mm x 10 µm cross sectional area and 30 µm in length were fabricated from both unirradiated and irradiated Ni single crystal samples along <100> and <110> crystal orientations. The samples were tested at nominal displacement rates of 5 and 500 nm/s. The investigation found strain rate sensitivity to be suppressed as a result of irradiation across both crystal orientations. The <100> and <110> crystal orientation exhibited differing failure mechanisms but showed similar CRSS values. Their fracture stress was greatly increased as a result of irradiation and it was accompanied by complete disappearance of ductility as they exhibited brittle fracture.