Sources of acoustic emission generated during the plastic deformation of 7075 aluminum alloy

The plastic deformation of crystalline solids will in general result in the generation of acoustic emission. Identifying the actual sources of the acoustic emission is difficult since the data may be comprised of emissions from several sources which may be operating either independently or cooperatively. By using a series of testing procedures and simultaneously measuring the dislocation damping while testing, it has been possible to identify the major sources of acoustic emission in 7075-T6 and 7075-T651 aluminum alloys. For the 7075-T651 alloy essentially all of the emission is from the fracture of small intermetallic precipitates dispersed within the matrix. For the alloy in the T-6 temper there is additional acoustic emission occurring at the onset of plastic deformation due to break-away and subsequent motion of dislocation line segments from their pinning points. formerly graduate student at the University of Denver, Denver, CO.