Eddy Current Testing Based Non-Destructive Inspection for Metal 3D Additive Manufacturing Objects With HTS-SQUID

In this work, we applied eddy-current-testing-based HTS-SQUID non-destructive inspection (ECT-based HTS-SQUID NDI) system for inspection of metal 3D additive manufacturing (AM) objects, which were made of AlSi10Mg powder with powder bed fusion (PBF) method. The inspection system combines an ECT probe with an HTS-SQUID gradiometer as high sensitive readout magnetic sensor in low frequency range to overcome disadvantage of conventional ECT. We prepared 5 samples with different densities by changing parameters in the PBF process. Densities of the samples #1–#5 were estimated to be 2.65, 2.64, 2.62, 2.58, and 2.51 g/cm
³
, respectively. The samples were measured by the inspection system with an excitation current of 20 mA at 1.6 kHz, and lift-off of about 1 mm. In inspection results, anomalous magnetic patterns appeared on the sample #3, #4 and #5. The inspection results were verified with X-ray CT scanning. Comparison between the ECT inspection and the X-ray CT results reveals that the positions of the anomalous magnetic patterns show strong correlation with the positions of high porosity existing in the samples.