Molecular dynamics simulation of the effect of irradiation defects on the mechanical properties of gold

Gold (Au) is a key coating material for electrical connectors in extreme irradiation environments for its excellent electrical conductivity and environmental stability. However, the response mechanism of its mechanical properties to irradiation-induced defects remains unclear. We employed molecular dynamics (MD) simulations to systematically investigate the effects of Frenkel pairs (FPs) with different concentrations on the mechanical behaviour of Au with the (100) orientation under uniaxial tension and compression along the [100] direction, shear on the (001) plane, and hydrostatic loading. Results show that: under uniaxial tension, compression and shear loading, the elastic modulus, ultimate strength, and maximum strain of Au decrease monotonically with the increase of defect concentration, indicating a significant deterioration effect of defects on plastic deformation; under hydrostatic load, the stress–strain curves of different defect concentrations almost overlap, indicating that the hydrostatic response is dominated by short-range atomic bonding, and the modulation effect of defects is negligible; Microscopically, 1/6 Shockley partial dislocations dominate all deformation modes due to Au’s low stacking fault energy. This work clarifies the differential regulation of irradiation defects on Au’s mechanical responses, supporting structural design and reliability evaluation of Au coatings for irradiation-exposed electrical connectors.