Hot torsion tests to model the deformation behavior of aluminium alloys at hot working temperatures

Knowledge of the deformation behavior of aluminium alloys at hot working temperatures is very important for high temperature manufacturing processes such as hot extrusion. Hot torsion tests were adopted to model this property in this paper. Constitutive equations for stress and strain were developed based on the functional relationship between torque and twist, which enables the material constants to be identified directly from the hot torsion test data. Hot torsion tests were conducted with the material AA5252 over a range of twist rate from 0.015 to 14.9 rev s(-1) and for each twist rate at an initial temperature range of 350-550 degrees C, respectively, which produced data to validate the constitutive equations with the proposed linear regression and the non-linear iteration formats to identify the material constants. A good agreement between the experimental data and the predicted results has been achieved, which demonstrates that the proposed constitutive equations and the methods of determination of the material constants are suitable to model the high temperature deformation behavior of aluminium alloys, which also demonstrates that hot torsion tests can not only produce data to identify material constants but also serve as a basis for the development of constitutive equations. (C) 1997 Elsevier Science S.A.