The development of reinforced conductors, with high electrical conductivity and high strength, is essential to provide non-destructive high pulsed magnetic fields over 80 Tesla: a compromise is obtained with Cu-based continuous nanofilamentary wires (2 GPa ultimate tensile strength and 0.6 µohm.cm electrical resistivity at 77K). The fabrication process of these nanocomposite wires is based on severe plastic deformation applied by accumulative drawing and bundling (ADB), leading to a multi-scale copper matrix containing up to N=855 (4.4 109) continuous and parallel niobium fibers. Three ways of optimization have been investigated: they deal with the geometry of the reinforcement, the material and the process.
Effects of size and geometry on the plasticity of high strength copper/tantalum nanofilamentary conductors obtained by severe plastic deformation,V. Vidal, L. Thilly, F. Lecouturier, P.-O. Renault, Acta Materiala Vol 54 Iss 4 (2006) pp 1063-1075
Cu nanowhiskers embedded in Nb nanotubes inside a multiscale Cu matrix: the way to reach extreme mechanical properties in high strength conductors, V. Vidal, L. Thilly, F. Lecouturier, P.-O. Renault, Scripta Materiala , vol 57 (3) (2007) 245-248
Plasticity of nanostructured Cu-Nb-based wires: strengthening mechanisms revealed by in-situ deformation under neutrons, V. Vidal, L. Thilly, S. Van Petegem, U. Stuhr, F. Lecouturier, P.-O. Renault and H. Van Swygenhoven, Scripta Mat, vol 60 (2009) 171-174
A new criterion for the elasto-plastic transition in nanomaterials: application to size and composite effects on Cu-Nb nanocomposite wires , L. Thilly, S. Van Petegem, P.O Renault, F. Lecouturier, V. Vidal, B. Schmitt, H. Van Swygenhoven, Acta Mat, vol 57 (2009) 3157-3169