Conductive nanolamellar Cu/martensite wire with high strength

Cu wires can be significantly strengthened without losing much conductivity if a continuous nanolamellar structure with Cu and a strong second constituent is achieved. We report on a nanolamellar Cu/steel wire fabricated by repetitive hot-pressing, forging, rolling and subsequent wire drawing. Austenization and quenching in liquid nitrogen resulted in a Cu/martensite structure, exhibiting tensile strength of 1220 MPa. The electrical conductivity of the wire was measured to be about 60% International Annealed Copper Standard (IACS), which was comparable with Cu/Fe fabricated by alloying and casting. In situ tensile tests under high energy X-ray diffraction were utilized to explore the deformation behavior of the wire. It was found that the martensite carried about 60% of the load, accounting for the high strength.