The microstructure of computer generated nanocrystalline coppers is simulat
ed by using molecular dynamics with the Finnis-Sinclair potential, analysed
by means of radial distribution functions, coordination number, atomic ene
rgy and local crystalline order. The influence of the grain size on the nan
ocrystalline structure is studied. The results reveal that as the grain siz
e is reduced, the grain boundary shows no significant structural difference
, but the grain interior becomes more disordered, and their structural diff
erence diminishes gradually; however, the density and the atomic average en
ergy of the grain boundary present different tendencies from those of the g
rain interior.