Acoustic emission from deformed magnesium alloy based composites

Magnesium alloys based composites were deformed at ambient temperature. The acoustic emission (AE) was detected in situ during deformation. The time dependence of the AE count rate was measured at two threshold levels. Two AE peaks were found. The peak observed at the onset of plastic deformation was ascribed to massive twinning and dislocation slip, and the second, broader maximum was caused mainly by fibre breakage and debonding at the fibre-matrix interfaces. The AE activity was significantly influenced by the load transfer from the matrix to the fibres.