Ultrasonic flaw detection of discontinuous defects in magnesium alloy materials

摘要

Phased array ultrasonic testing, an effective ultrasonic testing (UT) technology, has been widelyused in steel inspection because of its high accuracy, sensitivity, and efficiency. However, as its application inas-cast magnesium alloys has just begun, more research is needed. Considering the important role of the gaincompensation in quantifying defects in magnesium alloys by ultrasonic phased array technology, the effectsof microstructure, the position, size, and overlap of defects, and boundary distance (distance from the defectposition to the side surface of the test casting) on gain compensation of as-cast AZ80 and AZ31 magnesiumalloys were studied. Results show the gain compensation increases with the increase of grain size. There is astrict linear positive correlation between gain compensation and defect depth, but such relationship no longerexists due to the defects overlap, orientation and boundary distance. In addition, there is a strict linear negativecorrelation between the gain compensation and defect size.