Swift heavy ion irradiation of zirconium alloy: Deleterious effects on thermal and mechanical properties

Zirconium alloy, used as cladding and structural material for reactor fuel assembly, will undergo harsh neutron irradiation environment. Swift heavy ion irradiation is one of the applicable methods to simulate typical neutron damage in Zr alloy. In present investigation, Zr alloy was irradiated at 300°C and 700°C by 80 MeV Ni⁹⁺ ions with two different doses of 4.35×10¹⁵ cm^-2 and 8.7× 10¹⁵ cm^-2, which correspond to peak values of 5 dpa and 10 dpa. Three complementary analysis techniques, nanoindentation, laser-based photothermal reflectance thermal conductivity measurement technique and TEM were used to study irradiation damage before and after implantation. Results show that ion implantation enhances the alloy hardness and with the fluence increases and temperature decreases, hardness increases accordingly. The deduction of thermal diffusivity was also found after irradiation. These results are expected to deepen our understanding of Zr alloy and provide effective data for material optimization.