Improved detection of surface defects at sample edges using high-frequency eddy current amplitude and phase measurements

The detection of surface cracks at or close to sample edges is a challenging problem because the interaction eddy current with edge can make it difficult distinguish changes in signal due defect. Samples poor electrical conductivity such as titanium alloys used extensively aerospace applications be more inspect low amplitude currents induced them and increased electromagnetic skin depths lower conductivity. As fatigue manufacturing defects often occur edges, challenges detecting small an important research area address. High-frequency over 10 MHz are transmit-receive configuration using two solenoid type coils adjacent each other. While conventional sensors commonly designed for operating frequencies into region, supporting electronics here will positioned immediately behind improve stability reduce noise. magnitude phase voltage on transmit receiver measured, finite element modelling validate experimental measurements gain insight system behaviour. Small down 1 mm easily detected, corner alloy excellent signal-to-noise.