Estudo de uma nova liga de alumínio envelhecida natural e artificialmente

Abstract

Aluminum alloys are currently of great importance in modern industry, being one of the most versatile non-ferrous metals in casting, due to its infinite recyclable potential, maintaining its physicochemical properties. However, the aluminum production chain has high polluting potential when considering its primary route. It is in this context that the process under study aims to investigate and compare the mechanical properties of a molten alloy by means of secondary route (recycling), by means of tests of hardness, in the obtained material of the laboratory foundry and later treated thermally, by the treatment T6 solubilization with artificial aging and analysis of natural aging. The molten material came from a blend of aluminum alloys, since it came from industrialized beverage cans, in which aluminum alloys of the 3XXX, 5XXX and 5XXX classes were present, and the inclusion of the copper of class C1XX as an alloying element, from Electrical wires. After obtaining the experimental alloys, Brinell hardness of similar alloys of the class in which the alloys of the 2XXX series are found, evaluating the experimental alloys after thermal treatments T1 and T6 involving solubilization, natural and artificial aging. The hard solution hardening from the addition of copper were satisfactory in relation to Brinell hardness increase. However, the T1 and T6 treatments were not satisfactory when analyzed using the Brinell hardness averages, taking into account the deviations around these means in the data sets evaluated. The absence of higher hardnesses resulting from the precipitation of Guinier-Preston (GP) zones may be related to the presence of iron and silicon, as impurities capable of causing a change in the solidification sequence, leading to the appearance of primary phases containing Iron or silicon prior to crystallization of the aluminum grains. These phases containing iron or silicon have the possibility to grow freely generating coarse crystals in the liquid phase, reducing the resistance of the alloy.