Abstract
Resulting from torsion tests, the paper deals with hot workability of the Zr-stabilized aluminium alloy 2014 to improve mechanical properties due to the presence of the Al₃Zr precipitations. In general, the torsion tests, registering values of the torque M_k along with a number of revolutions N, and consequently leading to a stress-strain curve, enable to obtain information on ductility of the investigated material. Measured at the different temperature and stress rate, T and ε, respectively, the stress-strain curves exhibit rapid increase up to the peak value σ_p to be followed by a gradual decrease to the material fracture, accordingly without a steady state usually observed before the fracture. Finally, resulting from the stress decrease, and consequently using an analytical model, the relative softening RS and consequently the material fracture are determined. The presented experimental results exhibit a decrease of ductility, as a property related to workability, with an increase and a decrease of ε and T, respectively, and consequently optimal values of ε, T are obtained.

Key words
aluminium alloy, torsion test, ductility

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