Caracterização microestrutural e mecânica de uma liga Al-Zn-Si-Mg-Cu obtida por conformação por spray

Abstract

Aluminum is the third most abundant element in the Earth's crust, with a wide range of applications in domestic, automotive, and aerospace industries. Aluminum alloys can be classified as either mechanically worked or cast, and further subdivided into heat-treatable and non-heat-treatable types. Among the various alloy families, the 7XXX series stands out for its high mechanical strength combined with low density approximately three times lower than that of steel which makes it widely used, especially in the aerospace industry. This high strength is attributed to the addition of elements such as zinc, magnesium, copper, and silicon, whose concentration variations provide specific characteristics, resulting in improved mechanical performance and reduced density. In addition to chemical composition, the production method also strongly influences the final properties of the material. Alloys obtained by spray forming exhibit a refined and homogeneous microstructure, although this process inherently presents porosity as a disadvantage. In the present study, porosity ranged from 0.35% to 3.87%, with higher concentrations near the substrate, associated with gas entrapment and the initial impact of particles during deposition. The resulting microstructure exhibited equiaxed grains with an average size of 24 μm, predominantly composed of the α-Al, Mg₂Si, and Al₂Cu phases. Vickers microhardness tests showed values between 102.60 HV and 143.30 HV, indicating good homogeneity and a clear correlation between grain refinement and increased hardness. These results confirm the potential of the spray forming process for producing high-performance aluminum alloys, although porosity remains a factor to be further optimized in future studies.