Ultra-high mechanical strength and high electrical conductivity nanotwinned CuPd foils

Ultra-high strength nanotwinned CuPd foils were fabricated by rotary electroplating with the addition of tetraamminepalladium (II) sulfate. The incorporation of Pd significantly enhanced the mechanical properties, achieving an ultimate tensile strength of 860 MPa and a yield strength of 681 MPa. Unlike conventional Cu alloys, the electrical conductivity remained as high as ∼80% IACS. The addition of Pd induced pronounced grain refinement and reduced twin spacing, contributing to the strengthening of the Cu foils. Furthermore, the CuPd foils exhibited improved structural stability after annealing at 100 °C for 2 h. These results demonstrate that Pd incorporation is an effective strategy to achieve a superior combination of strength and conductivity in electroplated Cu foils.