Investigation On The Magnetic Detection And Imaging Technology For The Aluminum Alloy

Aluminum and Aluminum alloy is used in great quantities such as the aerospace,aviation, transportation, etc. In order to ensure its application security, thecorresponding quality control requirements are becoming more and more serious.Although the nondestructive testing technology for aluminum alloy has been widelystudied, such as ultrasonic, ray and eddy current testing technology, etc, but the methodhas many problems, they cannot meet the detection for the aluminum alloy. Theaccident rate which aluminum alloy material quality problem lead to is high in length,for this,the paper puts forward a kind of magnetic nondestructive testing method inmagnetic field environment.The magnetic properties of aluminum alloy are analyzed in this paper firstly, itproves that aluminum alloy is the paramagnetic material, it lays the foundation for theanalysis of the principle of magnetic detection; According to the differences of therelative magnetic permeability of the defects and the specimens, putting forward thedetection principle of magnetic method; The preset artificial holes and slot modaldefects are detected, the measured results shows that the magnetic signal has theobvious exception in the artificial defects. Through the detection for the natural defectswhich existing in the aluminum alloy, the results of the detection are analyzed andtested by metallographic and microscopic structure, the abnormal of the magnetic fieldwhich appeared in the measurement is consistent with the natural defects. The thin-plate(2mm) aluminum alloy is detected, it can detect the preset defects and the natural defectwhich existing in the aluminum alloy; The weld of the friction stir welding (FSW) isdetected, it can detect these tiny defects such as channel holes, porosity and closeddefects; Through the repetitive experimental study in the different conditions, it provesthat magnetic testing method has a good repeatability; It proves that the principle of themagnetic testing method is correct. According to the principle of the attenuation ofenergy, it derived the algorithm of the relative magnetic permeability and using thedifferent of the relative magnetic permeability, it derived the principle of the2Dimaging for the magnetic method and imaging showed; The results show that themechanism of the magnetic testing method is clear, the method is reliable and the repeatability is good, it can good to satisfy the demand of the detection for aluminumalloy. This topic has guiding significance for the effective detection of aluminum alloy.