TY - JOUR
T1 - Molecular dynamics investigation of the interaction of dislocations with carbides in BCC Fe
AU - Granberg, Fredric
AU - Terentyev, Dmitry
AU - Nordlund, Kai
N1 - Score=10
PY - 2015/1/7
Y1 - 2015/1/7
N2 - Different types of carbides are present in many steels used as structural materials. To safely use steel in demanding environments, like nuclear power plants, it is important to know how defects will affect the mechanical properties of the material. In this study, the effect of carbide precipitates on the edge dislocation movement is investigated. Three different types of carbides were investigated by means of molecular dynamics, with a Tersoff-like bond order interatomic potential by Henriksson et al. The obstacles were 4 nm in diameter and were of Fe3C- (cementite-), Fe23C6- and Cr23C6-type. The critical unpinning stress was calculated for each type at different temperatures, to get the temperature-dependent obstacle strength. The results showed a decreasing critical stress with increasing temperature, consistent with previous studies. The critical unpinning stress was seen to be dependent on the type of carbide, but the differences were small. A difference was also observed between the obstacles with the same structure, but with different composition. This study shows the relation between the existing Cr23C6 carbide and the experimentally non-existing Fe23C6 carbide, which needs to be used as a model system for investigations with interatomic potentials not able to describe the interaction of Cr in the Fe–C-system. We found the difference to be a between 7% and 10% higher critical unpinning stress for the chromium carbide, than for the iron carbide of the same type.
AB - Different types of carbides are present in many steels used as structural materials. To safely use steel in demanding environments, like nuclear power plants, it is important to know how defects will affect the mechanical properties of the material. In this study, the effect of carbide precipitates on the edge dislocation movement is investigated. Three different types of carbides were investigated by means of molecular dynamics, with a Tersoff-like bond order interatomic potential by Henriksson et al. The obstacles were 4 nm in diameter and were of Fe3C- (cementite-), Fe23C6- and Cr23C6-type. The critical unpinning stress was calculated for each type at different temperatures, to get the temperature-dependent obstacle strength. The results showed a decreasing critical stress with increasing temperature, consistent with previous studies. The critical unpinning stress was seen to be dependent on the type of carbide, but the differences were small. A difference was also observed between the obstacles with the same structure, but with different composition. This study shows the relation between the existing Cr23C6 carbide and the experimentally non-existing Fe23C6 carbide, which needs to be used as a model system for investigations with interatomic potentials not able to describe the interaction of Cr in the Fe–C-system. We found the difference to be a between 7% and 10% higher critical unpinning stress for the chromium carbide, than for the iron carbide of the same type.
KW - dislocation
KW - molecular dynamics
KW - precipitate
KW - carbide
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/34933262
U2 - 10.1016/j.nimb.2015.01.007
DO - 10.1016/j.nimb.2015.01.007
M3 - Article
SN - 0168-583X
VL - 352
SP - 77
EP - 80
JO - Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
ER -