Volume 7, Issue 3 (May 1979)
Acoustic Emission Monitoring of High-Temperature Cyclic Oxidation Damage in a Titanium-Aluminum-Vanadium Alloy
The feasibility of using acoustic emission techniques to monitor high-temperature thermal cycling oxidation damage in Ti-6Al-4V was studied between 600 and 900°C. Acoustic emission distribution analysis was applied to discriminate between different mechanical processes that lead to spalling of the oxide layers. It has been proven that acoustic emission follows very closely the exact material oxidation damage mechanism. Plastic deformation and partial stress relief in the oxide alloy system give rise to increasing emission of low peak amplitude pulses. Cracking and fracture of the oxide's scale, followed by spalling, produce a high rate of acoustic emission, with an increased fraction of high peak amplitude pulses. Nondestructive monitoring of oxidation damage in Ti-6Al-4V by acoustic emission was shown to be able to predict the onset of catastrophic spalling of the oxide's scale.