ACOUSTIC-EMISSION SPECTRUM AND ITS ORIENTATION DEPENDENCE IN COPPER SINGLE-CRYSTALS

Defect dynamics in copper single crystals is investigated using a mode rn acoustic emission technique including analysis of the shape and pow er spectra of individual pulses. Crystals with various tensile orienta tions providing different dislocation behaviors such as single and mul tiple glide, formation of cells and Lomer-Cottrell locks, etc., are ex amined. Features of AE corresponding to stages I, II and III of plasti c deformation are discussed in terms of statistical treatment of spect ral parameters. It is shown that the AE spectra are sensitive to the t ransitions of deformation stages. The results of AE analysis are discu ssed from the viewpoint of relationships between dislocation emergence to a free surface and dislocation breaking away from pinning points.