Study Of Copper Nanostructures By Molecular Dynamics Simulations

With the development of nano-technology, a series of nanomaterials have been prepared for the use of microelectronic device. As the miniaturized of device, the size of the film come to nanoscale. The external condition (such as temperature and stress) will directly affect the structure of these nanomaterals.In this paper, the structural and mechanical behavior of Cu nanobelts under axial loading (elongation and compression process) is studied by Molecular Dynamics (MD) simulations method.We perform MD simulations under the axial mechanical loading with an strain rate of±8.0×108s-1 (+ is stand for the elongation process and– is stand for the compression process)along z-axis in the temperature of 300K. The results show that the nanobelt reoriented both in the elongation and compression process. However, the reorientation atom configurations are quite different in the two loading process. In the elongation process, the nanobelt fully transforms from the initial configuration with <100> axial and four {100} lateral surfaces into a new configuration with <112> axial and two {111} lateral surfaces and two {110} lateral surfaces. In the elongation process, only part of the four lateral surfaces of the nanobelt reoriented from the initial {100} planes into {111} planes because of some unclear reasons.To analysis the structure transition in detail, we find that the reorientation is caused by the motion and propagation of dislocation, and the different reorientation results are caused by the dislocation move on the (1 1? 1?) plane along different <112> directions. After understanding the reorientation mechanism, we analyze the driving force of the initial dislocation nucleation and the propagation of dislocation. Then we analyze the stress-strain, potential-strain, kinetic-strain relations in the loading process.In the end, we study the effect of simulation conditions (temperature, strain rate, size).