Computer simulation of local atomic displacements in alloys. Application to Guinier–Preston zones in Al–Cu

Abstract

A new computer program has been developed for the simulation of local atomic displacements in alloys with face-centered-cubic and body-centered-cubic lattices. The combined use of this program with the Gehlen–Cohen program for the simulation of chemical short-range order completely describes atomic fluctuations in alloys. The method has been applied to the structural simulation of Guinier–Preston (GP) zones in an Al–Cu alloy, using the experimental data of Matsubara & Cohen [Acta Metall. (1985), 33, 1945–1955]. Characteristic displacements of atoms have been observed around the GP zones and new structural models including local displacements have been proposed for a single-layer zone and several multilayer zones.