Abstract
In this work, we have performed an atomic-level study by combining Molecular Dynamics (MD) and Monte Carlo (MC) techniques, employing recently developed Fe-Cr interatomic potentials fitted to ab initio data. The MC method was used to investigate the equilibrium arrangement of Cr atoms in an Fe-Cr matrix containing a dislocation loop. The results reveal that Cr atoms segregate to the tensile strain region and the dissolution temperature is about 50-100 degrees above the solubility limit.
The atomic configurations obtained by MC were then used to study the interaction of dislocations with the 'enriched' loops. It was revealed that depinning stress is higher for the 'enriched' loops and the complete absorption of loops on a dislocation line is suppressed. The reason for this has been rationalized in terms of the mechanisms involved in the non-elastic interaction between a dislocation line and dislocation loop. These results clearly show that local micro-chemical changes in the core of dislocation loops have important consequences for the mobility of loops and their interaction with dislocations.
