Hardening of Ionic Crystals by Neutron and Gamma Irradiation: Study of the NaCl and KCl Single Crystals

Abstract

The effect of neutron or gamma irradiation on the critical shear stress of sodium chloride and potassium chloride crystals has been studied. Until the irradiation dosage reached 1016 nvt, the rate of increase in the critical shear stresses was very small. However, critical shear stress of these crystals increased markedly when the dosage of the neutron irradiation exceeded 1016 nvt. At the total neutron dosage of 5×1017 nvt, the critical shear stress of sodium chloride and potassium chloride increased about 13 times and three times, respectively. Gamma irradiation caused significant hardening of NaCl when the dosage exceeded 107 R. When the irradiation dosage reached 3×108 R, the critical shear stress of NaCl increased about 11 times. The preirradiated sodium chloride crystals were annealed in the temperature range of 200°–300°C, and the activation energy for the recovery of radiation hardening was found to be 0.35–0.48 eV.