How Cr changes the dislocation core structure of α-Fe: the role of magnetism.
Cr is a critical alloying element in ferritic steels and its effect on the dislocation core structure of α-Fe is examined computationally using a quantum mechanics/molecular mechanics method. We find that Cr can significantly change the dislocation core structure of Fe where magnetism plays a crucial role. The strain-dependent magnetic interaction between Cr and the host Fe atoms is responsible for the dislocation core structure. When Cr is at the tension side of the slip plane, the Cr-Fe magnetic interaction is repulsive, which lowers the dislocation energy and pins the dislocation. When Cr occupies the compression side of the slip plane, the Cr-Fe interaction is attractive which increases the dislocation energy and promotes the dislocation to break away from  Cr.
Department of Physics and Astronomy, California State University Northridge, Northridge, CA 91330-8268, USA.
Xu
X
Zhang
Gang
G
Lu
D000497:Alloys / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D003198:Computer Simulation; D005290:Ferric Compounds / Q000737:chemistry*; D060328:Magnetic Phenomena; D011789:Quantum Theory
D000497:Alloys; D005290:Ferric Compounds; D002857:Chromium