Luca Sorrentino

In this work, for the first time thin, sheets of AA8006 aluminum alloy, that are commonly used for food packaging, were mechanically characterized through an unconventional free-forming technique that was performed at room temperature. This technique constitutes an economically effective solution to determine the constitutive equation of a metal sheet subjected to two-axes stresses. This state of stress reproduces the behavior of the material during the forming process better than the more traditional tensile test, which involves uniaxial stress. Specifically, the material constants were determined by using a simplified analytical model applied to the results of the experimental tests of the free forming process carried out at room temperature and constant pressure. Therefore, the obtained material constant values were used to simulate the same free-forming tests using FEM. In conclusion, the numerical results were in agreement with the experimental ones, thus confirming the goodness of the developed numerical model.

Powder Bed Fusion (PBF) is a popular additive manufacturing technology due to its high build resolution and ability to produce microscale geometries without the use of additional support. Despite the many benefits of PBF, there are still some limitations associated with the materials to be built. A critical industrial limit is the aging of PA12 powder, which is the degradation of its physical and chemical properties due to high temperatures and long building cycles of the powder that is not directly fused into the final part but supports the part under construction. This powder is now being used to make another part in order to reduce manufacturing costs. The mechanical properties of the built parts are reduced due to the reused powder. The current study aims to characterize powder aging using experimental tests such as Differential Scanning Calorimetry, Dynamic Mechanical Analysis, and Thermogravimetric Analysis to define the physical and chemical parameters of the powder that will be used inside a simulation software to optimize the process.