Nondestructive evaluation of cavitation in an Al–Mg material deformed under creep conditions

Cavitation was examined in an Al–Mg solid-solution alloy deformed in tension at 400 °C under conditions providing solute-drag creep, which can produce tensile ductilities from 100% to over 300%. Two nondestructive evaluation techniques were employed to measure the extent of cavitation: ultra-high-resolution x-ray computed tomography and pulse-echo ultrasonic evaluation. Subsequent to nondestructive evaluation, the sample was sectioned for examination by standard metallographic techniques. Metallographic examination confirmed that both nondestructive techniques accurately indicated the extent of cavitation. Ultrasonic testing provided a practical means of distinguishing material with cavities from that without cavities. Ultrahigh- resolution x-ray computed tomography provided an accurate three-dimensional image of internal cavitation.