Stress aging of Al-Cu alloys: Computer modeling

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