Ultrahigh high-strain-rate superplasticity in a nanostructured high-entropy alloy.

Superplasticity describes a material's ability to sustain large plastic deformation in the form of a tensile elongation to over 400% of its original length, but is generally observed only at a low strain rate (~10 s), which results in long processing times that are economically undesirable for mass production. Superplasticity at high strain rates in excess of 10 s, required for viable industry-scale application, has usually only been achieved in low-strength aluminium and magnesium alloys. Here, we present a superplastic elongation to 2000% of the original length at a high strain rate of 5 × 10 s in an Al(CoCrFeMnNi) (at%) high-entropy alloy nanostructured using high-pressure torsion.