Abstract
Atomic simulations of shear deformation of aluminum and coppernanocrystalline models are performed to determine the influences ofdefect plane energies on defect structures in nanocrystallinemetals. In aluminum models with high stacking fault energy, deformation twins can be observed in the case of the specific crystalorientation which is the same one as that expected analytically. Inthis case, extrinsic stacking faults always form in the early stage ofthe formation of intrinsic stacking faults. It is also observed thatnew crystal slip generates in an extended stacking fault in anothercrystal orientation in aluminum. In order to clarify the appearancemechanism of these defects in aluminum, we use the dislocation theoryand nudged elastic band method, and necessary conditions to formdeformation twin in aluminum are discussed.
