On the Room-Temperature Mechanical Properties of an Ion-Irradiated TiZrNbHfTa Refractory High Entropy Alloy
Refractory high-entropy alloys (RHEAs) are potential candidate materials for use in next-generation nuclear reactors due to their excellent mechanical performance at high temperatures. Here, we investigate the microstructure and mechanical properties of the nanocrystalline RHEA TiZrNbHfTa before and after irradiation with He2+ ions to determine radiation-induced property changes. Using nanoindentation and in situ microtensile testing we find only small changes in hardness after irradiation but a significant increase in yield and ultimate tensile strength without loss in ductility. This is associated with radiation hardening and a shift from shear localization failure with smooth fracture surfaces to a fracture morphology consisting of fine dimples and intergranular failure characteristics. Overall, the material shows excellent damage-tolerant properties with good combinations of strength and ductility both prior to and after ion irradiation.
The authors acknowledge the support of the Australian Nuclear Science & Technology Organisation (ANSTO) in providing expertise and facilities critical to this work—with special thanks to Colin Hobman for fabrication of testing equipment, Joel Davis for his support in preparing TEM specimens in the FIB, Ken Short for his help with nanoindentation, Tao Wei for performing the ion irradiation experiments, and the Centre for Accelerator Science for use of the 2 MV STAR tandem accelerator. In addition, the authors thank Microscopy Australia at the Electron Microscope Unit within the Mark Wainwright Analytical Centre at UNSW Sydney for technical assistance and use of their facilities. Additionally, M.M. would like to express gratitude for the financial support provided by the Australian Government [Award: Research Training Program (RTP) Scholarship] and by the Australian Institute of Nuclear Science and Engineering (AINSE) Limited [Award: Residential Student Scholarship (RSS)] who made this research possible.
Conflict of interest
The authors declare that they have no conflict of interest.
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