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Superplasticity — the ability of a material to sustain large plastic deformation — has been demonstrated in a number of metallic, intermetallic and ceramic systems. Conditions considered necessary for superplasticity are a stable fine-grained microstructure and a temperature higher than 0.5 T_m (where T_m is the melting point of the matrix). Superplastic behaviour is of industrial interest, as it forms the basis of a fabrication method that canbeused to produce components having complex shapes from materials that are hard to machine, such as metal matrix composites and intermetallics. Use of superplastic forming may become even more widespread if lower deformation temperatures can be attained. Here we present observations of low-temperature superplasticity in nanocrystalline nickel, a nanocrystalline aluminium alloy (1420-Al), and nanocrystalline nickel aluminide (Ni₃Al). The nanocrystalline nickel was found …