A determination of the elastic energy of dislocation loops from coarsening kinetics

The rate of coarsening of prismatic dislocation loops in quench-aged aluminium containing 6 ×10−3 at.-% indium during bulk annealing in the range 383—403 K was measured using quantitative transmission electron microscopy. The average loop area was found to be directly proportional to the time of annealing and the activation energy for the rate-controlling process to be 1·23±0·04 eV. Both time and temperature dependences were in accordance with that predicted by an analysis due to Kirchner (1973). This analysis was used to derive dislocation energies from the coarsening rates. A mean value of 6·2±1·1 × 10−9 Jm−1 (6·2±1.1 × 10−4 erg cm−1) was obtained compared with a value of 1·75 × 10−9 Jm−1 calculated on the basis of elasticity theory.