Stress aging of Al-Cu alloys: Computer modeling

Stress aging of Al-Cu alloys was modeled to demonstrate the stress orientin g effect of the theta "/theta ' -precipitate structures. The precipitation sequence of the Guinier-Preston (GP) zones --> theta " --> theta ' phases w as treated as a continuous evolution-the parameters, such as lattice misfit s, of the second-phase particles change depending on their sizes. Numerical simulations were conducted using a concomitant precipitation model that in corporates interaction energy between the external stress and the strain fi elds due to the lattice misfits of the second phases. The simulations repro duced most of the main features of the effects that were observed in experi mental measurements. (C) 2001 Acta Materialia Inc. Published by Elsevier Sc ience Ltd. All rights reserved.