Mechanical engineer, Lawrence Livermore Laboratory, Livermore, Calif.
Professor of mechanical engineeringconsultant, University of CaliforniaLawrence Livermore Laboratory, DavisLivermore, Calif.Calif.
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.
Paper ID: JTE10158J