Introducing dislocation climb by bulk diffusion in discrete dislocation dynamics

Abstract

We report a method to incorporate dislocation climb controlled by bulk diffusion in a three-dimensional discrete dislocation dynamics (DDD) simulation for fcc metals. In this model we couple the vacancy diffusion theory to the DDD in order to obtain the climb rate of the dislocation segments. The capability of the model to reproduce the motion of climbing dislocations is examined by calculating several test-cases of pure climb-related phenomena and comparing the results with existing analytical predictions and experimental observations. As test-cases, the DDD is used to study the activation of Bardeen–Herring sources upon the application of an external stress or under vacancy supersaturation. Loop shrinkage and expansion due to vacancy emission or absorption is shown to be well described by our model. In particular, the model naturally describes the coarsening of a population of loops having different sizes.

Keywords:

• dislocation climb
• dislocation loops
• diffusion
• dislocation dynamics

Acknowledgments

The authors gratefully thank Dr. G. Martin, Prof. J.P. Poirier, Prof. J. Friedel, Prof. J. Grilhé, Dr. D. Caillard and Dr. A. Barbu for fruitful discussions and suggestions.