The Effect of Temperature on Anisotropy Properties of an Aluminium Alloy

The temperature influence on the mechanical behaviour during plastic deformation of an AA5754-O aluminium alloy has been investigated by several experimental tests. First, monotonous tensile tests were carried out from room temperature up to 200A degrees C with a classical tensile machine and with a less conventional testing apparatus involving the heating of the sample by Joule effect. With this second testing apparatus, the strain fields and tensile curves were obtained in function of temperature by means of a non-contacting optical 3D deformation measuring system. Moreover, shear tests were performed in the same temperature range. It is shown that the anisotropy coefficients are rather constant within this temperature range, with a relative variation less than 8%. For both tensile and shear tests, the stress levels are similar at the beginning of straining at room temperature and 150A degrees C, except that the Portevin-Le Chatelier (PLC) phenomenon disappears at elevated temperature, and then evolves differently. At 200A degrees C, the stress level is clearly below whatever the deformation. In the framework of drawing process, the formability of this alloy at temperatures higher than 150A degrees C seems to be improved.