Precipitate induced anisotropy effects in aluminium alloys

T. Foglesong; H. Sehitoglu; H.J. Maeir

doi:doi:10.1051/jp4:20030193

Issue		J. Phys. IV France Volume 105, March 2003


Page(s)		239 - 246
DOI		https://doi.org/10.1051/jp4:20030193

J. Phys. IV France 105 (2003) 239
DOI: 10.1051/jp4:20030193

Precipitate induced anisotropy effects in aluminium alloys

T. Foglesong¹, H. Sehitoglu² and H.J. Maeir³

¹ ExxonMobil Upstream Research Company, 3120 Buffalo Speedway, Houston, TX 77252, U.S.A.
² Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign, 140 Mechanical Engineering Building, 1206 West Green Street, Urbana, IL 61801, U.S.A
³ University Paderborn, Lehrstul für Werkstoffkunde, FB10, 33098 Paderborn, Germany

Abstract
A physically-based hardening formulation, derived from dislocation theory, was incorporated into a polycrystal model and applied to a binary aluminum-copper precipitation-hardened alloy. The alloy was heat treated at 190 $^{\circ}$ C and 260 $^{\circ}$ C for various times and was studied in both polycrystal and single crystal forms. Single crystals eliminated the complicating effects of grain boundaries allowing clear determination of the active deformation mechanisms, as well as a detailed study of the effect of precipitates on the flow anisotropy behavior. Different deformation mechanisms were observed corresponding to the degree of coherency between the precipitate and the matrix. The influence of precipitate-induced anisotropy on single crystal flow behavior was clearly established, again relating to the precipitate character and included in the hardening description. The physically-based hardening formulation was comprised of both statistical and geometrical storage components. Model results were compared to single crystal and polycrystal compression experiments. Accurate simulations were obtained for most of the aging conditions and the correct trends due to precipitate-induced anisotropy were predicted.