Plastic deformation of pure silicon nanocrystals by molecular dynamics

This paper is the results of high speed deformations of pure silicon nano c rystals using the molecular dynamics. The paper suggests that plastic defor mation may be possible for the silicon with a high speed deformqation even at room temperature. The potential used was three body Stillinger-Weber pot ential The size of a crystal is 6(X) X 16(Y) X 2 (Z)[nm]. x, y and z axes are take n in [(1) over bar 10], [(1) over bar (1) over bar 2] and [111] direction, respectively. [110] direction is the cutting direction. (111) is the cuttin g plane and a slip plane. A sharp vertical solid edge was advanced in the x direction with a speed of 10 m/s. The simulation was extended up to 400,00 0 steps. In front of the cutting edge, atoms are pushed up. The chip becomes amorpho us. The creation of dislocations was not clearly observed, instead the amor phous region extended on the surface of cutting. Another nano size single crystal was compressed using molecular dynamic met hod. The surfaces are (111), ((1) over bar 10) and((1) over bar (1) over ba r 2). The compressed direction was [(1) over bar (1) over bar (1) over bar] . It was found that silicon crystals are possible to be compressed with a h igh speed deformation. (C) 1999 Acta Metallurgica Inc.