Study Of Configuration Of Edge Dislocations In Fee Copper From Molecular Dynamics Simulation

The shortest lattice vector, and therefore the most likely Burgers vector to formdislocations in fcc (face-centered cubic) metals is a/2<110>. The edge dislocations in fccmetals is considered consisting of two adjacent atomic planes according to the arrangementrules of the atomic layers. However, the current study reports hold on different views onthe results, so the further research of the configuration of edge dislocations in fcc metals isnot only of theoretical significance, but also is important for the understanding themechanism of plastic deformation of materials, strengthening mechanisms and otherphysical and chemical properties.The edge dislocations of fcc metals copper has been simulated from moleculardynamics simulation with EAM (embedded-atom method) potentials at0K, we alsostudied energy and configuration of the edge dislocations. This article starts from the threerespects, which include modeling, the effect of the forming of dislocations on crystallinevolume as well as the configuration and energy of edge dislocations, extended dislocations,screw dislocations, mixed dislocations, dislocations generated by concretionary crystal infcc metals Cu, focuses on the configuration of edge dislocations in fcc metals Cu, studiesthe configuration and energy of common types of dislocations in Cu at different states.Although our article takes Cu for example, most of the qualitative conclusions which wereobtained from the article are fitted for other fcc metals.Considering all the simulated results, we make the following conclusions:(1) In fccmetals Cu, the formation of edge dislocations makes the crystalline volume dilate, whilethe formation of screw dislocations makes no effect on the volume, and the generation ofmixed dislocations induces bigger crystalline expansion, most likely because of theexcessive atomic planes which was forced into the crystal when producing dislocations (2)The edge dislocations which was considered consisting of two adjacent atomic planes doesnot exist in fcc metals Cu, it will split into extended dislocations and this process happensautomatically without additional activated energy, The crystalline energy decreases afterthe decomposition of the dislocations, which is coordinated with the Lowest EnergyPrinciple.(3) Based on the study of edge dislocations and extended dislocations in fcc metals Cu, Au, Ag, Al, Ni, Pd, we can infer that the perfect dislocations in fcc metals willsplit into partial dislocations, which generates two different kinds of energy peaks on theslip plane, and the differences between the two energy peaks not only have relationshipswith the relative position in which the atoms of the energy peaks locate, but with the typesof the perfect dislocations.(4) Based on the study of the concretionary crystalline model infcc metals Cu, we can conclude that the energy of atoms around the dislocations in fccmetals Cu will increase and the width of extended dislocations after decomposition willdecrease under the conditions of the coexistence of varieties of dislocations, compared tothe single type of dislocations.