Aluminum as a pure metal has low strength and poor mechanical properties. For use in high- strength structural applications, pure aluminum must be alloyed. Aluminum alloys of the 6XXX group have outstanding qualities, such as strength and formability. The main alloying elements are Mg and Si, which form the compound Mg2Si. One such alloy is the EN AW 6082 alloy, which is used in the automotive industry, where weight savings is a critical requirement for reduced fuel consumption and exhaust emissions. In addition to being lightweight, aluminium forgings provide superior structural rigidity, high strength, good corrosion resistance and fatigue resistance.
The main objective of the thesis was to metallographically prepare samples of aluminum alloy EN AW 6082 for a light microscope and to compare the microstructure between aluminum forging with heat treatment T6 and aluminum forging, which is air-cooled after forging. Grain sizes were determined, the hardness of the samples was measured, and the electrical resistance of the samples was measured with a Foerster, sigmatest 2.069.
After forging the samples, the second sample was heat treated in accordance with the T6 procedure.The microstructure was prepared for phase observation and crystal grain observation. Crystal grains in the microstructure forged by the heat treatment have grown strongly along the peripheral zone. The material is strongly subjected to extensive shear deformation on the surface layer, compared to the middle, and when the temperature rises again, recrystallization occurs and the grains grow. By measuring hardness, we found that heat treatment is key to achieving high hardness and that recrystallised grains do not impair strength or mechanical properties.
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