Synergistic Optimization of Electrical and Mechanical Properties in High-Conductivity Pure Copper via Super-Gravity

Super-gravity technology was applied during the solidification of high-conductivity No. 2 oxygen-free copper (TU2) to achieve synergistic optimization of its electrical and mechanical properties. Theoretically, super-gravity promoted grain refinement by increasing the nucleation rate (via dendrite fragmentation and enhanced heterogeneous nucleation) and reducing the grain growth rate (due to increased melt viscosity). Experimentally, applying the super-gravity field specifically during solidification proved essential for effective microstructural modification. As the gravity coefficient (G) increased from 1 to 1000, grain size was significantly refined, especially when G > 500. Consequently, Vickers hardness increased from 59 to 95 kg/mm2 and ultimate tensile strength rose from 112.2 to 124.7 MPa, while electrical conductivity remained nearly unchanged (from 106.92% to 106.38% IACS). The slight initial increase in conductivity was attributed to reduced porosity, followed by a minor decrease due to enhanced grain boundary scattering. This study demonstrated that super-gravity solidification was an effective strategy for fabricating high-conductivity metallic materials with simultaneously improved strength and hardness.