Structure analysis by diffraction of amorphous zones created by Ni ion implantation into pure Al

The implantation of Ni ions into pure Al leads to the formation of similar to 10 nm amorphous zones (AZ) which induce diffuse rings in the diffraction pattern in addition to the diffraction spots of the crystal. Measurements by energy dispersive spectrometry and electron energy loss spectrometry att ributed to the amorphous zones an average Ni concentration of 25 at%. The e xact structure of these AZ is still unknown. The structure is characterized here by both the total and partial radial distribution functions (RDF). St ructure factor deduced from experiments is compared to calculated one. For this purpose, molecular dynamic (MD) simulations are used to model the AZ s tructure. The RDF are determined using this structure and analytical calcul ation of the diffraction pattern is achieved. Simulations of the diffractio n pattern of the simulated MD sample using both a kinematic and a dynamic a pproach are achieved to refine the analytical procedure used on the experim ental diffraction patterns. It appears that the amorphous structure is well reproduced by the MD simulations. Analytical calculation reveals the prese nce of a well-established chemical order in the amorphous material. (C) 200 0 Elsevier Science B.V. All rights reserved.