Exceptional room-temperature plasticity in amorphous alumina nanotubes fabricated by magnetic hard anodisationElectronic supplementary information (ESI) available: Videos illustrate the peeling and manipulation of the alumina nanotubes with a micromanipulator, and their breaking and placement across trenches etched in a silicon wafer. Video 1. Peeling off a single alumina nanotube, and plastic deformation to form a kink. Video 2. Bending and breaking a single nanotube, and laying it across the s

Crystalline aluminum oxide is a brittle ceramic material. Here we show that individual alumina nanotubes with internal and external radii of ∼15 nm and ∼50 nm, respectively and lengths of the order of 100 μm can be readily separated from amorphous alumina membranes fabricated by a hard anodisation process under a magnetic field of up to 1.5 T. The ceramic nanotubes are extremely flexible and exhibit an exceptional plasticity of ±70% at room temperature without breaking. Elastic properties investigated by the double clamped beam method include a tensile strength of 4.1 GPa, corresponding to a breaking strain of 5%. These values are respectively 17 and 70 times greater than those of polycrystalline alumina fibres. The plasticity of anodic amorphous alumina helps explain the formation of ordered arrays of nanopores in the alumina membranes. Amorphous alumina nanotubes produced by hard anodisation in a magnetic field exhibit extraordinary plasticity and a breaking strain of 5%.