Efficient production of kilometer-scale ultrafine aluminum wire with superior strength and electrical conductivity

The rapid development of new energy vehicles has generated considerable interest in the efficient production of ultrafine aluminum electronic wiring harnesses with superior strength and electrical conductivity (EC). However, achieving a balance between strength and EC/ductility remains a challenge. To overcome the trade-off relation, we precisely controlled the grain size and grain boundary structure by using ultrafine aluminum powders (similar to 1 mu m) as the starting material, and introduced dislocations into the as-sintered sample to enhance the strain rate sensitivity via cold deformation. In the cold-deformed sample, a unique mechanical response was observed: the elongation increased with deformation. Meanwhile, the strength and EC maintained to be a high level. Based on the unique properties, we successfully fabricated kilometer-scale ultrafine aluminum wire (0.2 mm in diameter) by cold deformation without any intermediate annealing, realizing high strength (206 MPa) and high EC (59.1% IACS, International Annealed Copper Standard) simultaneously. Our work provides a new concept and a new processing route to efficiently produce ultrafine aluminum electronic wiring harness with excellent properties.