Electrical conductivity field analysis for evaluation of FSW joints in AA6013 and AA7075 alloys

To fully characterize Friction Stir Welding several techniques are required, mainly destructive, as hardness or metallographic testing. However, there is still a need for developing dedicated methods, preferably non-destructive. Electrical conductivity, based on a different physical principle, may constitute an alternative. The present study aims to characterize the electrical conductivity in friction stir welds and to investigate the correlation between this and the hardness observed in different regions of a weld. An eddy current planar probe was used for the measurements at different depths. For this, welded samples were machined in steps and in ramp and scans along orthogonal axis were performed. The results were correlated with the microstructural modifications. A close match between the electrical conductivity field and the microstructure was observed. A good correlation with hardness was noticed, suggesting that the non-destructive test has the potential to complement or substitute destructive methods as hardness tests.