Innovative Concept and Application of EC Probe For Inspection of Friction Stir Welds

In this paper a new NDT system is presented. The system is composed by a planar eddy currents probe (IOnic probe), electronic devices for signal generation, conditioning and conversion, automated mechanized scanning and analysis software. This new IOnic probe allows a 3D induced current in the material, and an easy interpretation of the signal based, not on the absolute value, but on a comprehensible perturbation of the signal. This provides enhanced liftoff immunity and improved sensitivity for defects detection. The IOnic system was developed mostly to be used for the micro-defects detection on aluminum solid state processed alloys by FSW. The features of some material imperfections lead to significant difficulties in their identification when using existent NDT techniques. Results from an analytical simulation fully agree with the experiments. The experimental results in AA2024 welded by FSW clearly show that this system is able to detect imperfections around 50 ?m, which contribute to increase the reliability on NDT of micro imperfections. EC conventional probes are also applied as material characterization technique. Results are compared to microstructural analysis and hardness measurements show that eddy current can map the different zones providing a deeper understanding on precipitate dispersion and grain shape and size.