Acoustic-emission diagnostics of the initiation of fatigue fracture of 1201-T aluminum alloy

We consider the specific features of generation of acoustic emission caused by the fatigue fracture of thermally strengthened 1201-T aluminum alloy. Based on the metallographic and fractographic investigations and analysis of typical signals, we establish that this alloy is destroyed by the brittle-ductile mechanism. The character of acoustic-emission radiation depends on the alloy microstructure and mechanical properties, and the area of the formed defect is proportional to the sum of amplitudes of the recorded signals. The passage from the initiation of a fatigue crack to its stable propagation is accompanied by a sharp jump of the acoustic-emission activity.