Formation of Point Defects during Plastic Deformation and Their Subsequent Annealing Behavior

Abstract

The formation of point defects during plastic deformation and their subsequent interactions with dislocations in high-purity copper was studied using a low-temperature strain-aging technique. The point-defect-dislocation interaction gave rise to a small yield point whose magnitude depended on the temperature and time of aging after deformation. The annealing kinetics indicated that two types of point defects were formed by deformation in concentrations which depended on the prestrain and prior history of the specimen. A mechanism for the point-defect annealing was proposed to account for the experimental results and was used to calculate the diffusion-activation energy of the defects in the lattice and along the dislocations. Based on this mechanism, the defects were tentatively identified as the interstitial and the divacancy. The temperature dependence of the yield point was examined and was shown to be consistent with an elastic interaction due to the dilatation around the point defects. The results indicated that the point defects retained their identity on arrival at the dislocation rather than becoming incorporated into the dislocation structure.