Electron and photon emission accompanying deformation and fracture of polycarbonate

Abstract

AbstractElectron and photon emission accompanying tensile loading and failure of polycarbonate show weak emissions during the onset of neck formation and intense emissions during the fracture event itself. These results are interpreted in terms of formation of active species by bond breaking followed by emission driven by energy released by recombination. Fast time scale measurements during fracture show that intense electron and photon emission typically begins about 50 μs prior to the completion of fracture and is most intense at the completion of fracture. The gradual onset reflects the final stages of growth of the failure‐initiating defect. Defect growth was monitored by measuring the intensity of a light beam transmitted through the gauge length of the sample; the transmission is sensitive to scattering by surface and bulk defects. A marked decrease in transmission begins some tens of ms prior to fracture due to scattering from the fracture‐initiating defect. These measurements allow accurate correlations of defect growth with the onset of the electron and photon signals. © 1993 John Wiley & Sons, Inc.