APPLICATION OF EDDY CURRENT TECHNIQUES TO INSPECT FRICTION SPOT WELDS IN ALUMINIUM ALLOY AA2024 AND A COMPOSITE MATERIAL

New materials and production technologies demand improved non-destructive techniques for inspection and defect evaluation, especially when critical safety applications are involved. In this paper two Non-destructive Testing (NDT) applications are presented: the inspection of Friction Spot Welding (FSpW) of AA2024-T351 with and without Alclad (TM) and a composite material GLAss-REinforced Fibre Metal Laminate (GLARE (R)) with artificial defects. The two applications were tested by Eddy Currents (EC), using both conventional planar spiral probes and a new EC probe developed by some of the authors, called IOnic probe. Four different FSpW conditions were produced and tested in 2 mm-thick plates of duraluminium with and without Alclad (TM). Three defects were introduced in GLARE (R) aiming to compare the reliability of the different NDT approaches. The experimental results show that the IOnic probe is able to identify different levels of FSpW quality regions by a distinctive perturbation on the output signal, whereas conventional probe cannot distinguish the different FSpW conditions. Regarding the GLARE (R) application, it was found that IOnic probe can detect the deeper defect easier than the conventional EC probe.