MICROSTRUCTURAL ANALYSIS OF SIMULATED LIQUID AND AMORPHOUS NI

Molecular dynamics simulations and a systematic analysis of the local atomic structure have been done to investigate the microstructure of l iquid and amorphous Ni. The n-body Gupta potential, based on the secon d moment approximation of a tight-binding Hamiltonian, was used to mod el the metallic bonding of the system. The calculated pair distributio n function (PDF) of liquid and amorphous Ni are in agreement with expe rimental measurements. A decomposition of the first and second peaks o f the PDF into components according to the local environment of the pa irs shows that the atomic coordination of the liquid phase contains a high abundance of icosahedral and distorted icosahedral structures. Cr ystalline and icosahedral (regular and distorted) atomic configuration s contribute in approximately the same proportion to the short-range o rder of the amorphous phase. These results indicate that n-body intera ctions favor the formation of crystalline order in amorphous metals.