Irradiation effect on the morphology change of quasi-nano-filamentary copper–silver composite wire

Quasi-nano-filamentary copper–silver composite wire was fabricated by heavy deep drawing, which was irradiated and annealed to study irradiation induced phase transformations behavior. Mechanical properties of the quasi-nano-filamentary composites like ultimate tensile strength, yield strength, elongation and micro-Vickers hardness were 1015 MPa, 985 MPa, 4.9% and 107 Hv, respectively. The specimens with 3 mm in diameter for reduction of nuclear waste were irradiated in CT hole of High-flux Advanced Neutron Application Reactor (HANARO) of KAERI for 36 days at 320 °C with the maximum neutron fluence of 4.8 × 1020 n/cm2 (E > 1.0 MeV). The gamma heating rate was in the range of 2.0–6.45 W/g. Irradiation embrittlement was observed in the irradiated specimen. The hardness of the irradiated specimen is abruptly decreased by additional annealing for 3 h at 300 °C, which resulted from the morphology change of polycrystalline filaments and reduction of residual stress of the composites. The ratio of grain boundary energy of silver to silver free surface energy is evaluated as 1.977.