Molecular dynamics study of shear and tensile deformation of bicrystalline aluminum

This paper describes shear and tensile deformation of bicrystalline aluminum by computer molecular dynamics. A bicrystal model with a [001] (310) ∑=5 tilt grain boundary is used for simulations. The simulations show that the effect of temperature on both the shear and tensile deformation is represented by a Boltzmann factor exp (-Q/kBT) and that the deformation is thermally activated in a typical manner. We found that the activation energy Q for the high temperature range, where T is higher than approximately 500 K to 600 K, is significantly larger than that for the low temperature range. This result shows that there are different deformation mechanisms between high and low temperatures. The activation energy difference is considered to be caused by a structural transition at the grain boundary.