Large-scale production of nano-twinned, ultrafine-grained copper

Large-scale production of high purity (99.999%), nano-twinned, and ultrafine-grained copper foils (22 μm thick) was successfully implemented by the use of nanoscale multilayer technology. The process allows the production of up to fourteen 10 cm diameter foils during a single deposition run with high levels of reproducibility. Mechanical tests demonstrate that the strength of the Cu foils (σy ∼ 540–690 MPa) compares favorably to ultrafine-grained copper samples produced by other methods.