An attempt to determine the binding energy of point defects and dislocations in sodium chloride by internal friction measurements

Abstract

An attempt has been made to measure the binding energy of point defects and dislocations in sodium chloride by employing the Granato and Lücke theory of internal friction. Three problems have been encountered in interpreting the experimental results. First, the calculated energies are an order of magnitude larger than those obtained by other workers. Second, they are negative and thus suggest a repulsion instead of an attraction. Third, the value calculated from the intercepts of Granato-Lücke plots disagrees with that obtained from the slopes. Solutions are suggested for the first two problems, but we are unable to explain the third. Under the conditions of this experiment the Granato and Lücke theory is not able to explain the observed behaviour.