Berlin 2005 – scientific programme

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.152: Poster

Monday, March 7, 2005, 14:00–18:00, Poster TU C

AMR Sensor Array for the Detection of Defects in Aluminum Laser Welds — •Kai Allweins and Marc von Kreutzbruck — Institut für Angewandte Physik, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392 Giessen

Increasing demands in material testing have led to growing interest for advanced and reliable electro-magnetic testing methods. We present eddy current measurements with an AMR sensor array for the detection of imperfections in aluminum laser welds used in automotive industry. Usually material defects in laser welds are micro-cracks as well as porosities with diameters often as small as 100 µm. Measurements of laser welds with a width of 1-2 mm in an AlMg3 aluminum alloy with a thickness of more than 1 mm were performed. The welds contain reference defects or unknown defects. The separation of defect signals from noise caused by the weld’s surface texture required additional efforts in signal processing and simulations. Due to the field sensitivity of about 100 pT/√Hz and high spatial resolution of the implemented AMR sensor array small porosities with a radius of 65 µm could be detected in a depth of up to 1 mm with a sufficiently high signal-to-noise ratio.