In the final thesis, we used a solid-state, pulsed Nd:YAG laser to melt heat-treated aluminum alloy 7075-T6 and discussed the influence of the laser beam spot size and the laser's power on the penetration depth and change in the hardness of the treated surface compared to the base material. Residual stresses in the sample were also measured. We have demonstrated that the laser beam energy density does not have a significant effect on the attained hardness of the melted surface. The microstructure turned into fine-grained, and the hardness decreased in terms of the delivered Al 7075-T6 quality. If an Al 7075-T0 alloy, not pre-treated with aging, had been used, the hardness would have increased. In the individual traces of the laser beam, the residual stresses are noticeably larger than in the larger melted surface obtained by overlaying the traces.
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