Characteristics of the interaction of Cu-rich precipitates with irradiation-produced defects in α-Fe

Abstract

The interaction between copper-rich precipitates in α-iron and either vacancies or self-interstitial atoms and their clusters is studied by atomic-scale modelling. Results are compared with predictions of elasticity theory and interpreted in terms of size misfit of precipitates and defects, and the modulus and cohesive energy differences between iron and copper. Interstitial defects are repelled by precipitates at large distance but, like vacancies, attracted at small distance. Hence, copper precipitates in iron can be sinks for both vacancy and interstitial defects, and can act as strong recombination centres under irradiation conditions. This leads to a tentative explanation for the mixed Cu–Fe structure of precipitates and the absence of precipitate growth under neutron irradiation conditions. More generally, both vacancy and interstitial defects may be strongly bound to precipitates with weaker cohesion than the matrix.

Acknowledgements

This work was performed under a research grant from the UK Engineering and Physical Sciences Research Council and partly sponsored by the Division of Materials Sciences and Engineering, US Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC.