Characterization of mechanical properties and formability of a superplastic Al-Mg alloy

In order to develop a reliable constitutive model for predicting formability and springback of sheet metals during superplastic forming (SPF) and quick plastic forming (QPF), characterization of elastic-plastic behavior, as well as formability of the material is essential. In the present study, the module of elasticity, uniaxial flow behavior and anisotropy, as well as the forming limit curve (FLC) of one of an SPF/QPF grade AA5083 was investigated. The variation of Young's modulus with temperature was measured from the uniaxial tensile tests for four temperatures ranging from 25 to 500 degrees C. The impact of temperature and strain rate on the flow behavior of the material was investigated via uniaxial tensile tests for three temperatures (420, 450, and 480 degrees C) and at three strain rates (0.001, 0.01, and 0.1 s(-1)). The dependency of the flow stress on the material orientation with respect to the rolling direction (0, 45, and 90 degrees) was assessed using uniaxial tensile tests at a constant temperature. In addition, the evolution of plastic anisotropy with plastic strain and strain rate was assessed by measuring the Lankford coefficient (r-value). Finally, the FLC of the material at 450 degrees C was characterized according to Nakazima tests procedure for three strain paths (i.e. uniaxial tension, plane strain, and biaxial tension).