Relationship between Grain Boundary Structures and Mechanical Properties of Nanocrystalline Metals with Different Stacking Fault Energy Using Atomic Scale Computational Experiments
Tomotsugu SHIMOKAWA, Toshiyasu KINARI, and Sukenori SHINTAKU
Abstract:Mechanical properties of nanocrystalline metals of which the grain size is below about 100nm are affected by the relationship between the intergranular and intragranular deformation. Intragranular deformation in nanocrystalline metals could be caused by the movement of perfect dislocations or Shockley's partial dislocations, hence stacking fault energy is one of the important value to control the internal structure. Moreover, the proportion of the grain boundary region dramatically increases with grain size decreasing, hence it is also important to investigate the effects of individual grain boundary structures and the distribution of grain boundary characteristics on the macroscopic mechanical properties of polycrystalline materials. In this study, we investigate deformation mechanism and mechanical properties of nanocrystalline Al and Cu that show the different stacking fault energy using molecular dynamics simulations, and we also consider the effects of grain boundary misorientation distributions on the mechanical properties of such materials. Key Words:Molecular dynamics, Atomic simulation, Nanocrystalline material, Grain boundary, Intergranular fracture, Deformation twin, Partial dislocation, Stacking fault energy, Plastic deformation