| Popis: |
Magnesium has been considered an excellent candidate as lightweight structural material for many years, but the low ductility caused by its plastic deformation mechanism has always been a limitation of extensive application.In this work, we use molecular dynamics approach to simulate tensile test on single crystal and polycrystalline magnesium to investigate its tensile behavior and plastic deformation mechanism. In each tensile simulation on single crystal magnesium, we applied extensions with constant strain rate along each of the [1-210], [10-10] and [0001] direction at the temperature of 100 K, 200 K, 300 K, 400K and 500 K. Fromthese simulation, magnesium nanocrystals has shown strong anisotropy that the loading direction significantly influence the tensile strength as well as the deformation mechanism. At the same time, temperature plays an important role during the plastic deformation of magnesium. We also performed tension simulations on polycrystalline magnesium nanocrystals with number of grains equal to 1, 2, 3, 4 and 5 which are randomly generated using Voronoi tessellation. These simulations prove that the grain boundaries in polycrystalline models play a dominant role affecting the tensile behavior of magnesium. Grain boundaries affect the tensile strength, the formation of cracks and they act as source for slips and deformation twins. |
