In this study we investigated the mechanical properties of wrought aluminium alloys for transportation industry use. We focused on the strength properties, obtained by the friction stir welding process. In the experimental part, we took measurements of surface roughness and waveviness of friction stir welded joints in 2017A-4 and 7075-T6 aluminium
alloys that were welded using different welding parameters. We also measured the microhardness profile through the transverse cross-section of butt joints. After finding the correlation between measured values and the welding process parameters, macroscopic and microscopic analyses for the chosen specimen were performed. Then we investigate the possible correlation between measured microhardness extremes and microstructure properties. The topography analysis showed us that the highest value of mean roughness (5,4 µm) was observed in the direction parallel to the welding direction in the area where welding process at a feed per revolution of 25 rev/cm took place. The maxima of microhardness were observed at the upper layer of the welding sample that was welded at a feed per revolution of 16 rev/cm with a value of 170 HV0,2. In the lower layer of the same specimen, the minimum of 96 HV0,2 was measured.
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