Heat Treatment Selection and Forming Strategies for 6082 Aluminum Alloy

Abstract

Aluminum 6XXX alloys show high strength to weight ratios and are thus promising materials for today’s transport industry lightweight construction efforts. When considering both deformation and final mechanical properties, high ductility is interesting from the conformability point of view. On the other hand, high resistance is necessary in the automotive structural parts (which can be obtained through T6 precipitation heat treatment) but leads to reduced ductility. In order to increase aluminum alloys’ formability, warm forming is commonly applied. In contradiction to this, this article shows how the tensile deformation behavior of the 6082 T6 alloy is not affected by the temperature. In this work, the necessary formability values to obtain the parts are achieved, deforming the material under O annealed condition. But this strategy is focused on the formability perspective; therefore, the final mechanical properties do not achieve the necessary strength requirements. As a solution, the possibility of applying the T6 heat treatment after forming the parts (in annealed condition) is studied. A tensile characterization of the post-heat-treated specimens obtained from the deformed experimental part results in high flow stress levels, and thus, the strategy is validated. Nevertheless, the heat treatment leads to geometrical distortions in the final part, and thus, a last calibration step should be added to the forming process in order to obtain the desired shape.