The influence of grain size on acoustic emission characteristic in commercial-purity zirconium during tensile deformation

摘要

The influence of grain size on acoustic emission (AE) behavior during tension test in commercial-purity zirconium was investigated under a constant nominal strain rate at room temperature. Two deformation modes, dislocation slip and mechanical twinning, were found to be the physical sources for AE. The statistical analysis from metallographs showed that the quantity of mechanical twin gradually increased as grain size and tension strain increase. With grain size increased, the activity and intensity of the AE signals increased. The frequency distribution of the AE waveforms showed that two kinds of AE source were active with distinct frequency components during tension. By means of AE signal classification, the characteristic of AE due to dislocation slip and deformation twin were discussed respectively. The results showed that although dislocation was the dominant deformation mode, the primary AE source changed from dislocation to twin with the grain size increase. The AE activity due to twin was consistent with the metallographic evidence relating to the tensile deformation process.