Comprehensive Study on Microstructure and Mechanical Properties of Si Ion Irradiated Al 6063

Aluminum alloys are widely used as fuel cladding materials for research reactors. Neutron irradiation damage is a major concern in the nuclear industry, and it is of great interest to study irradiation damage by ions, which can cause similar damage to materials. In this study, Al 6063 alloy was irradiated with Si ions at 333 K up to 90 dpa to mimic the effects of both elemental Si, a transmutation product of thermal neutrons, and Frenkel pair formation, an effect of fast neutrons. The irradiation damage was investigated by transmission electron microscopy and the nanoindentation technique. The irradiated sample's net dislocation density was about 1.2·10¹⁴ m⁻² in the vicinity of the voids and 2·10¹⁴ m⁻² in the vicinity of the Si peak. The implanted Si peak concentration was ~ 6 at% at a depth of ~ 1100 nm. The formation of voids with an average size of 8 nm, and a peak number density of ~10²² m⁻³ was identified, and the void annihilation time dependence was found to be proportional to ( [Formula presented] )^0.25. The amorphous to crystalline structure transformation temperature of the intermetallic Al₈Fe₂Si occurs at 723 K and follows the Johnson-Mell-Avrami diffusion control model. The hardness and estimated ultimate tensile strength of the irradiated surface layer, obtained by the nanoindentation measurements, increased by ~65% in comparison to the unirradiated sample. A similar increase in yield stress and ultimate tensile strength published values of neutron irradiation damage, occurs at much higher dpa (~260 dpa). This difference is suggested to be related to the high dpa rate and higher at%Si/dpa ratio in the present ion irradiation experiments.