Volume 3, Issue 3 (May 1975)
Acoustic Emission Testing of Unflawed 7075-T6 Aluminum
Tensile tests were performed to study the differences in the continuous acoustic emission from 7075-T6 aluminum plates made by five manufacturers. The grain structures and the chemical compositions of these plates were determined. Results are given on a sixth plate, which emitted burst-type acoustic emission super-imposed on the continuous acoustic emission. The effect of orientation with respect to the rolling direction within a single plate was studied. Results from interrupted tensile tests are also reported; these tests were stopped at about 4.5% strain for different time periods before they were resumed. The tests indicate that acoustic emission is very sensitive to differences between plates of 7075-T6 aluminum that do not show up on a stress-strain curve. Furthermore, the dislocation mechanisms that cause the continuous acoustic emission in this aluminum alloy are altered by room temperature, diffusion-based aging.