Enhanced electrical conductivity and mechanical properties in thermally stable fine-grained copper wire

Abstract The rapid development of high-speed rail requires copper contact wire that simultaneously possesses excellent electrical conductivity, thermal stability and mechanical properties. Unfortunately, these are generally mutually exclusive Here, we demonstrate directional optimization microstructure overcome the strength-conductivity tradeoff in wire. We use rotary swaging to prepare with a fiber texture long ultrafine grains aligned along axis. exhibits high conductivity 97% international annealed standard (IACS), yield strength over 450 MPa, impact wear resistances, up 573 K for 1 h. Subsequent annealing enhances 103 % IACS while maintaining above 380 MPa. provide channel free electrons, low-angle grain boundaries between block dislocation slip crack propagation, lower ability boundary migration.