抄録
An effect of electron beam (EB) irradiation on the fracture resistance of soda lime glass was studied. EB-irradiation with small dose less than 1 MGy and low potential less than 170 keV could not change the plastic deformation energy to propagate the crack (Efp), which was estimated by fracture toughness (KIC) using standard indentation fracture method. On the other hand, EB irradiation of less than 0.43 MGy increased the plastic deformation energy to generate the crack (Ef). If EB-irradiation annihilated the spontaneous crack origins, it could be explained the increasing Ef value. In addition, if EB-irradiation formed dangling bonds in glassy network structure, they probably relaxed the residual stress and should prevent the crack generation. As the result of electron spin resonance spectra showed, the EB irradiation generated dangling bonds in the soda lime glass and partial relaxation of the residual strain mainly occurred around these dangling bonds of the weakly bonded metal (Na and Mg)-oxygen pairs in the network structure. The increased crack generation energy was therefore mainly due to the relaxation of the strongly bonded metal-oxygen atomic pairs in the network structure, as well as the annihilation of crack origin.
