Glide of dislocations in <1 1 1>{3 2 1} slip system: an atomistic study

Abstract

Atomistic calculations are performed to investigate plastic slip in the <1 1 1>{3 2 1} system in body-centred cubic iron. Several modern interatomic potentials, developed over the last decade, are applied to compute the stacking fault γ-line energy in the {3 2 1} plane and the results are compared with the ab initio prediction. The applied potentials have shown strong deviations, but several potentials acquired good qualitative agreement with the ab initio data. Depending on the applied potential, the lowest value of the Peierls stress for the edge dislocation (ED) is 50 MPa (Ackland and Bacon from 1997) and the highest is 550 MPa (Dudarev and Derlet from 2005), while for the screw dislocation it is much higher, in the range 1–2 GPa. At finite temperature, however, the flow stress of the ED is found to decrease exponentially reaching a negligible value at about 200 K, irrespective of the applied potential. On the basis of the data obtained using Ackland–Mendelev potential from 2004, we conclude that the slip resistance of the <1 1 1>{3 2 1} system is in between the resistance of the <1 1 1>{1 1 0} and <1 1 1>{1 1 2} slip systems.

Keywords:

• Dislocation
• iron
• molecular dynamics

Supplemental data

Supplemental data for this article can be accessed http://dx.doi.org/DOI10.1080/14786435.2015.1126369

Acknowledgements

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. The authors acknowledge the contribution of Xiangjun Shi to this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Euratom research and training programme 2014–2018 [grant number 633053].