Strain-rate cycling tests were carried out, with a superposed oscillatory stress, on single crystals which were doped with Cl- or I-. The relationship between the strain-rate sensitivity of the flow stress, and the stress decrement due to the superposed oscillatory stress, was stair-like and consisted of 3 regions. There were 2 plateau regions at low and high stress decrements, and an intermediate region where the strain-rate sensitivity decreased with increasing stress decrement. The stress at the first bending point, between the first plateau region and the middle one, was considered to be the effective stress due to Cl- or I-. This decreased with increasing temperature. The difference, between the strain-rate sensitivities at the first and second plateau regions, decreased with temperature. The difference was attributed to Cl- or I-. The interaction energies between a dislocation, and Cl- or I-, were 0.40 or 0.47eV; assuming that the force-distance profile was described by the Cottrell-Bilby relationship. The force–distance profile was different to that for KCl:Br-.

Investigation of Interaction between a Dislocation and a Cl- or I- Ion in NaBr Single Crystals. T.Ohgaku, M.Sakuda: Materials Science and Engineering A, 2003, 357[1-2], 55-60