Production, microstructural and mechanical characterization of spray formed Al-6 wt.% Fe alloy and pre-mixed Al-6 wt.% Fe/SiCP composite

Abstract Different batches of Al–6 wt.% Fe and of pre-composite Al–6 wt.% Fe/SiC powders were produced, via melting of aluminum followed by iron addition in the induction furnace of a gas atomizing unit, eventually adding in situ a suitable amount of SiC particulate. The inclusion of the reinforcing particles in the melt was enhanced by means of stirring under an argon shielding atmosphere. Gas atomization via sonic close-coupled discrete jet nozzles was thereafter performed, and a part of the spray cone was intercepted by a still substrate. The microstructural characterization of both the pre-composite powder and of the spray deposited samples was carried out by microscopy, image analysis and X-ray diffraction. The high viscosity of the matrix allowed to achieve a maximum volumetric fraction of reinforcement of around 10%. By means of X-ray stress analysis the residual stresses in the spray formed specimens were determined, and resulted to be compressive, and higher in the composite material. The elastic properties of the spray formed samples were determined by the flexural resonance test, carried out on prismatic samples cut from the spray formed samples, while their transverse strengths were determined by three points bend test.