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The deposition of steel powders on glass fiber reinforced polymer (GFRP) with the Cold Spray technique is investigated. Metallization of composite materials is still challenging when high-strength and dense powders, such as steel, are used due to excessive erosion of the polymer or disruption of the fibers during the deposition. To overcome these issues, low-pressure cold spray equipment has been used for the experimental campaign shown in this paper. Different coatings were obtained by using nitrogen as the carrier gas and different sets of pressure and standoff distance. Optimization of the process parameters, including the stratification of the laminate, has been carried out. Results of an initial study of the feasibility of the process and the influence of the different chosen spray conditions are exposed. In particular, the bonding mechanisms of steel powders and their morphology are discussed.

Cold spray deposition of aluminum powders on polyethylene reinforced with glass fibers has been studied. Different processing conditions, including different stratifications of the fiber-reinforced polymer used as a substrate, have been investigated to better understand the deposition mechanism. The experimental campaign has been conceived and tailored to highlight the influence of several process parameters on the deposition of the first layer of particles. The results obtained allowed to highlight and clarify the influence of standoff distance and gas pressure and also gave some insights concerning the effect of the substrate stratification. Guidelines regarding the design of the manufacturing process have been also released.

In this work, the mechanical behaviour of natural composite fibre sandwich panels is experimentally investigated. The composite sandwich panels are composed of a natural core made of Posidonia dried leaves reinforced with aluminium skins. The introduced material system is characterized by good structural behaviour (due to the aluminium skins) combined with the good thermal and acoustical insulation provided by the Posidonia core. Flexural and impact tests, characterized by different impact energies, have been performed on specimens with and without the aluminium skins, to preliminary assess the influence of the Posidonia core densities on the natural fibre sandwich mechanical behaviour.

The effects of different heat treatments on Inconel 718 parts produced through selective laser melting were investigated. Different heat treatments, carried out by varying both temperature and time, were performed on 10x10x10 mm3 cubes. Aiming to study the effects of the treatments, microhardness measurements, optical and SEM observations were carried out on both the treated and the untreated samples. The results obtained proved the effectiveness of the treatment, if the conditions are properly set, in producing the typical microstructure of the cast Inconel 718 that is the starting point for the conventional heat treatments. A predominant influence of the temperature was also highlighted.The effects of different heat treatments on Inconel 718 parts produced through selective laser melting were investigated. Different heat treatments, carried out by varying both temperature and time, were performed on 10x10x10 mm3 cubes. Aiming to study the effects of the treatments, microhardness measurements, optical and SEM observations were carried out on both the treated and the untreated samples. The results obtained proved the effectiveness of the treatment, if the conditions are properly set, in producing the typical microstructure of the cast Inconel 718 that is the starting point for the conventional heat treatments. A predominant influence of the temperature was also highlighted.

In this activity, customized panels for the CS deposition have been produced and aluminium has been deposited using air as a carrier gas. The custom-made panels were made with different matrix thicknesses on the surface in order to point out the influence of the fibres in the deposition and to study the feasibility and the growth of the coating. The polymer chosen for the matrix is polypropylene, widely used in the automotive sector, while for the reinforcements glass fibres have been used. Different process parameters have been examined in order to point out the influence of temperature, stand-off distance and pressure chosen, on the compaction and densification of the coating produced. In addition, morphological investigations were performed to further characterize the coatings deposited. It has been noticed that aluminium powders can be effectively deposited on polypropylene panels, leading to significantly better results when the thickness of the matrix is ​​sufficient to prevent the powders bouncing elastically on the fibres, while benefiting from the stiffening effect of the latter.

The use of hard metals, in particular for cutting tools, is becoming wider. Their manufacturing cost, higher than traditional steel, is compensated by an increased lifetime. This work involves the rheological characterization of a WC–Co compound, in order to evaluate its viscosity for different values of strain rate. Following this characterization, the data are implemented in a FEM code, in order to simulate the extrusion processes of such compounds to manufacture hard metal bars. This study highlights the importance of an accurate viscosity evaluation of these mixtures and the correct setting of FEM parameters in order to predict successfully extrusion processes. As an example, an analysis is presented for the case of cutting tools with helical holes for the passing of fluid coolant.

Cold roll forming is a process for plastic deformation, which allows realizing profiles, with a defined section and established length, from the plastic deformation of a metal sheet. The sheet is induced to cross several stands of rolls, arranged along the same axis of advancing. The rolls induce plastic deformation in the sheet and then lead it to the desired geometric configuration. In order to control the geometric parameters of the plate during the profiling, it was created a FEM model to simulate the final stage of the technological process, developed by an industrial production line of a company located in Naples (Italy), that sells tubes with several cross sections. In this phase, the semi-finished product, having a circular cross section, is forced to cross through four stands of rolls. In this way, it changes the geometric condition of the cross section from circular to square. The model was carried out using a non-linear calculation code, which allows analyzing the parameters of interest in the different process steps. The results, obtained numerically, were compared with the experimental ones through the measurement of five specimens, obtained directly from technological process. The values of percentage deviation, regarding the external dimension and the thickness, for each step of advancement, do not exceed the 3% of error. Then, the analysis results denote the capability to simulate the cold roll forming process using finite element method.