Structure and transport properties of nanolaminate Cu–Nb composite foils by a simple fabrication route

Bulk nanolaminate Cu–Nb composite foils were fabricated by a room temperature ball milling approach with or without additional cold rolling. The average thickness of individual lamellae is about 25 nm for Cu and 5 nm for Nb. As-milled foil shows (1 1 1)Cu and (1 1 0)Nb out-of-plane textures and a hardness of 445 HV. It is distinct from reported works showing that superconductivity with a low Tc of ∼2.0 K persists in Nb nanoparticles with an unusually low critical size of 5 nm for superconducting transition.