Processamento em estado sólido de desperdícios de alumínio

All the proposed objectives are specific, measurable and verifiable, being realistically achievable, based on the past experience of the partners, in related projects, and on the existing state of the art on solid-state recycling of metallic chips. Primary Objective: Development and optimisation of Solid-State Processing (SSP) tools, procedures and parameters for the direct recycling of aluminium wastes through coupled Cold Compaction (CC) and Friction Stir Extrusion (FSE). As already mentioned, both SSP technologies, CC and FSE, were already tested at the laboratory level. However, using CC as a pre-processing step in producing fully dense bulks, by FSE, was not reported in the literature at the time of the current proposal. By coupling these two technologies, it is expected to extend the use of FSE from the direct recycling of machining chips to the recycling of small size scraps, with diversified sizes and geometries. By performing the cold consolidation of the scraps, it is also envisaged to overcome another import FSE limitation, the scale-up of the technology to produce long extrusions, which, currently, is still limited by the capacity of performing the continuous feeding of chips in the FSE apparatus. Achieving the project Primary Objective will require accomplishing the following sub-objectives: 1)Adapting and instrumenting a lath machine for the execution of FSE. 2) Design of interchangeable tools, prone to be used in the CC of the aluminium wastes, into porous bulks, which will feed the FSE apparatus. 3) Performing the microstructural and mechanical characterization of the aluminium alloys (which will be converted into chips and other controlled geometry scraps), to produce data for the numerical simulation tasks. 4) Running numerical simulations aiming the optimization of CC and FSE tools geometry and dimensions. 5) Determining the best procedures and parameters for the CC of the aluminium wastes into porous bulks. 6) Performing the mechanical and morphological characterization of the porous bulks to determine the evolution of its density with CC conditions. 7) Determining the best procedures and parameters for the FSE of the porous bulks into fully dense material bars. 8) Performing the mechanical and microstructural characterization of the extruded products. 9) Developing a finite element thermo-mechanical model of the FSE process and validating it using experimental data (Temperature, force and torque). 10) Performing a parametric study on the influence of porous bulks properties (density and plastic properties of the metallic wastes) and FSE parameters, on FSE temperature and forces, to develop materials properties related process-windows. 11) Producing and testing porous bulks from contaminated aluminium wastes (with lubricants, for example) to determine its influence on the process-window and on the final properties of the extruded parts. As secondary self-related objectives of the project it can be identified, the improvement of the energy efficiency and the minimisation of material losses in the recycling of aluminium wastes. These aspects will be analysed in a specific project task, in which the energy consumption and material losses, in CC and FSE, will be compared with that of traditional recycling methods, to assess the environmental benefits of the coupled solid-state processing route.