Effects of Neutron Irradiation upon the Young's Modulus and Internal Friction of Copper Single Crystals

Abstract

Measurements of neutron irradiation effects upon the Young's modulus and logarithmic decrement of a set of copper single crystals of 99.999% purity have been made at room temperature. Interpretations of the results can best be given in terms of an oscillating dislocation line mechanism in which the oscillations are suppressed by the presence of interstitial atoms, vacancies, or some combination thereof. Comparisons of the results with the predictions of impurity line pinning are given. It is shown that an interpretation in this sense leads to generally accepted values for the dislocation densities and average segment lengths.